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 A187042 #24 Nov 30 2024 06:24:06 %S A187042 8,12,18,20,27,28,32,44,45,48,50,52,63,68,75,76,80,92,98,99,112,116, %T A187042 117,124,125,147,148,153,162,164,171,172,175,176,188,207,208,212,216, %U A187042 236,242,243,244,245,261,268,272,275,279,284,292,304,316,325,332,333,338 %N A187042 Numbers the expansion of which over distinct terms of A050376 contains the same number of primes and perfect squares. %C A187042 The sequence does not contain squarefree numbers or perfect squares. %C A187042 Initially the sequence matches A378494 (the intersection of A000379 and A026424). The first differences are the absence here of 120 and 168 and the inclusion here of 216. - _Peter Munn_, Jul 13 2024 (edited by _Paolo Xausa_, Nov 29 2024). %H A187042 Amiram Eldar, <a href="/A187042/b187042.txt">Table of n, a(n) for n = 1..10000</a> %e A187042 147 and 216 are in the sequence, since their expansions over distinct terms of A050376 are 3*49 and 2*3*4*9 respectively. Thus the expansion of 147 contains one prime and one perfect square, while the expansion of 216 contains two primes and two perfect squares. %t A187042 aQ[n_] := Total @ (d = IntegerDigits[Last /@ FactorInteger[n], 2])[[;; , -1]] == Total @ Flatten @d / 2; Select[Range[350], aQ] (* _Amiram Eldar_, Oct 01 2019 *) %Y A187042 Cf. A050376, A187039, A378494. %K A187042 nonn %O A187042 1,1 %A A187042 _Vladimir Shevelev_, Mar 02 2011 %E A187042 a(28)=153 inserted and more terms added by _Amiram Eldar_, Oct 01 2019