Rhonda number
An integer n is a Rhonda number to base b if the product of its digits in base b equals b×sum of prime factors of n (including multiplicity).[1]
The base 10 Rhonda numbers are 1568, 2835, 4752, 5265, 5439, 5664, 5824, 5832, 8526, 12985, 15625, 15698, 19435, 25284, 25662, 33475, 34935, 35581, 45951, 47265, 47594, ... (sequence A099542 in the OEIS), Rhonda numbers only exist in composite bases, since if b is prime, then the product of the digits of any number n in base b cannot be divisible by b, and if b = 1, then the product of the digits of any number n is 1, thus the sum of prime factors of n must be 1, but that is impossible.
Other bases[edit]
Base | Rhonda numbers | OEIS sequence |
4 | 10206, 11935, 12150, 16031, 45030, 94185, 113022, 114415, 191149, 244713, 259753, 374782, 392121, 503773, 649902, 703326, 716250, 764526, 883630, 884446, 912766, 980694, 980837, ... | A100968 |
6 | 855, 1029, 3813, 5577, 7040, 7304, 15104, 19136, 35350, 36992, 41031, 42009, 60368, 65536, 67821, 76880, 84525, 90601, 122831, 131175, 154570, 162565, 184009, 184585, 196504, ... | A100969 |
8 | 1836, 6318, 6622, 10530, 14500, 14739, 17655, 18550, 25398, 25956, 30562, 39215, 39325, 50875, 51429, 52887, 55611, 56420, 58548, 59731, 60604, 72358, 74620, 76581, 78780, 81370, 84180, 85949, ... | A100970 |
9 | 15540, 21054, 25331, 44360, 44660, 44733, 47652, 50560, 54944, 76857, 77142, 83334, 83694, 96448, 97944, 106575, 108273, 117624, 125952, 138966, 141204, 144236, ... | A100973 |
10 | 1568, 2835, 4752, 5265, 5439, 5664, 5824, 5832, 8526, 12985, 15625, 15698, 19435, 25284, 25662, 33475, 34935, 35581, 45951, 47265, 47594, 52374, 53176, 53742, 54479, 55272, 56356, 56718, 95232, ... | A099542 |
12 | 560, 800, 3993, 4425, 4602, 4888, 7315, 8296, 9315, 11849, 12028, 13034, 14828, 15052, 16264, 18511, 18906, 25619, 25875, 27176, 32742, 37264, 37523, 46035, ... | A100971 |
14 | 11475, 18655, 20565, 29631, 31725, 45387, 58404, 58667, 59950, 63945, 67525, 68904, 91245, 99603, 125543, 135196, 141141, 148645, 149575, 168270, 175577, ... | A100972 |
15 | 2392, 2472, 11468, 15873, 17424, 18126, 19152, 20079, 24388, 30758, 31150, 33004, 33550, 37925, 39483, 42550, 44714, 58870, 59605, 66950, 70182, 71485, 71709, 85557, 85848, 86241, 86591, 92150, ... | A100974 |
16 | 1000, 1134, 6776, 15912, 19624, 20043, 20355, 23946, 26296, 29070, 31906, 32292, 34236, 34521, 36465, 39066, 50055, 50986, 52341, 54340, 58088, 59541, 75867, 85870, 87150, 88182, 93058, 95944, 99674, ... | A100975 |
560 is the smallest number that is Rhonda number in some base (namely, base 12), and 1000 is the smallest number that is Rhonda number in two bases (namely, base 16 and base 36).
See also[edit]
References[edit]
- ↑ Looijen, M. (2016). Over getallen gesproken – Talking about numbers (in Nederlands). Van Haren Publishing. p. 350. ISBN 978-94-018-0028-0. Retrieved 18 October 2018. Search this book on
External links[edit]
- Weisstein, Eric W. "Rhonda Number". MathWorld.
- Walter Schneider, Rhonda Numbers
- Giovanni Resta, Rhonda number
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