This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A100974 #12 Feb 16 2025 08:32:55 %S A100974 2392,2472,11468,15873,17424,18126,19152,20079,24388,30758,31150, %T A100974 33004,33550,37925,39483,42550,44714,58870,59605,66950,70182,71485, %U A100974 71709,85557,85848,86241,86591,92150,110334,112671,113300,116270,120414 %N A100974 Integers that are Rhonda numbers to base 15. %C A100974 See A099542 for definition of Rhonda numbers and for some links. %H A100974 Reinhard Zumkeller, <a href="/A100974/b100974.txt">Table of n, a(n) for n = 1..1000</a> %H A100974 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/RhondaNumber.html">Rhonda Number</a> %e A100974 The product of the base 15 digits of 2392 is 10*9*7=630. The sum of the prime factors of 2392 is 3*2+13+23=42 and 630=15*42. So 2392 is a Rhonda number to base 15. %o A100974 (Haskell) %o A100974 a100974 n = a100974_list !! (n-1) %o A100974 a100974_list = filter (rhonda 15) $ iterate z 1 where %o A100974 z x = 1 + if r < 14 then x else 15 * z x' where (x', r) = divMod x 15 %o A100974 -- Function rhonda as in A099542. %o A100974 -- _Reinhard Zumkeller_, Mar 07 2015 %Y A100974 Cf. Rhonda numbers to other bases: A100968 (base 4), A100969 (base 6), A100970 (base 8), A100973 (base 9), A099542 (base 10), A100971 (base 12), A100972 (base 14), A100975 (base 16), A255735 (base 18), A255732 (base 20), A255736 (base 30), A255731 (base 60). %Y A100974 Cf. A001414, A027746, A255872. %Y A100974 Column k=8 of A291925. %K A100974 easy,nonn,base %O A100974 1,1 %A A100974 Mark Hudson (mrmarkhudson(AT)hotmail.com), Nov 25 2004