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 A364964 #6 Sep 01 2023 15:23:32 %S A364964 2,3,4,6,8,12,16,24,27,32,48,54,64,96,108,128,192,216,256,315,384,432, %T A364964 512,630,768,864,1024,1260,1536,1728,2048,2520,3003,3072,3456,4096, %U A364964 5040,6006,6144,6912,8192,10080,12012,12288,13824,16384,20160,24024,24576,27648,32768,40320,42757,48048,49152,55296,65536 %N A364964 Numbers k such that k is a multiple of A243071(k). %C A364964 For k > 1, if k is a term, then also 2*k is present in this sequence, and vice versa. %o A364964 (PARI) %o A364964 A243071(n) = if(n<=2, n-1, my(f=factor(n), p, p2=1, res=0); for(i=1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p*p2*(2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); ((3<<#binary(res\2))-res-1)); \\ (Combining programs given in A156552 and A054429) %o A364964 isA364964(n) = ((n>1)&&!(n%A243071(n))); %Y A364964 Sequence A163511(A364494(n)), for n>=0, sorted into ascending order. %Y A364964 Cf. A007283 (subsequence), A364965 (odd terms). %Y A364964 Cf. also A364497, A364550. %K A364964 nonn %O A364964 1,1 %A A364964 _Antti Karttunen_, Sep 01 2023