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 A185615 #16 Aug 11 2022 03:20:00 %S A185615 1,4,8,25,50,108,169,243,256,338,486,512,729,768,972,1024,1156,1215, %T A185615 2312,3375,5000,7921,8192,8748,10000,12800,15000,15842,20000,25000, %U A185615 50176,54289,85184,88209,100352,104976,108578,131072,176418,177147 %N A185615 Numbers k that divide A000201(k)^m for some integer m > 0, where A000201 is the lower Wythoff sequence. %C A185615 Let k = p_1^{e_1} * p_2^{e_2} * ... * p_r^{e_r}. Then k is in this sequence iff p_1*p_2*...*p_r divides A000201(k). %C A185615 Many of these terms are powers of Fibonacci numbers. %C A185615 Perhaps this is expected, since A000201(k) involves floor(k*phi). %e A185615 For n=8, A000201(8)=12. Since 8 divides 12^2, 8 is in this sequence. %e A185615 For n=9, A000201(9)=14. Since 9 cannot divide 14^m for any m, 9 is not in this sequence. %o A185615 (Python) %o A185615 from math import isqrt, prod %o A185615 from itertools import count, islice %o A185615 from sympy import primefactors %o A185615 def A185615_gen(startvalue=1): # generator of terms >= startvalue %o A185615 return filter(lambda n: not (n+isqrt(5*n**2)>>1)%prod(primefactors(n)),count(max(startvalue,1))) %o A185615 A185615_list = list(islice(A185615_gen(),30)) # _Chai Wah Wu_, Aug 10 2022 %Y A185615 Cf. A000201, A185616, A185617. %K A185615 nonn %O A185615 1,2 %A A185615 _Paul D. Hanna_ and _Sean A. Irvine_, Jan 31 2011