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 A365423 #5 Sep 04 2023 18:21:24
%S A365423 3,7,31,45,55,111,119,123,127,175,207,247,253,447,567,895,927,945,957,
%T A365423 959,987,1005,1007,1017,1503,1519,1887,1919,1983,2013,2023,2031,2037,
%U A365423 2045,3325,3567,3835,3839,3927,3965,4015,4025,4029,4031,4063,4085,4087,5887,7035,7095,7119,7163,7167,7679,7791,7839,7917,7931
%N A365423 Odd numbers k for which k and A163511(k) have the same prime signature.
%C A365423 See comments in A364297.
%o A365423 (PARI)
%o A365423 A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };
%o A365423 A163511(n) = if(!n, 1, my(p=2, t=1); while(n>1, if(!(n%2), (t*=p), p=nextprime(1+p)); n >>= 1); (t*p));
%o A365423 A365421(n) = (A046523(A163511(n))==A046523(n));
%o A365423 isA365423(n) = ((n%2)&&A365421(n));
%Y A365423 Odd terms in A365422.
%Y A365423 Cf. A000668 (subsequence), A046523, A163511, A278531, A364297, A365421.
%K A365423 nonn
%O A365423 1,1
%A A365423 _Antti Karttunen_, Sep 04 2023