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 A065334 #14 Feb 21 2021 03:16:12 %S A065334 0,1,0,2,0,1,0,3,0,0,0,2,0,0,0,4,0,1,0,0,0,0,0,3,0,0,0,0,0,0,0,5,0,0, %T A065334 0,2,0,0,0,0,0,0,0,0,0,0,0,4,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,6,0,0,0,0, %U A065334 0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,5,0,0,0,0,0,0,0,0,0 %N A065334 2-exponents to represent 3-smooth numbers (A065332). %C A065334 For k > 0 with A065332(k) > 0: A065332(k) = (2^a(k)) * (3^A065335(k)). %H A065334 Antti Karttunen, <a href="/A065334/b065334.txt">Table of n, a(n) for n = 1..16384</a> %H A065334 Antti Karttunen, <a href="/A065334/a065334.txt">Data supplement: n, a(n) computed for n = 1..100000</a> %F A065334 a(n) = A007814(n) * A065333(n). %t A065334 a[n_] := If[n/2^(e = IntegerExponent[n, 2])/3^IntegerExponent[n, 3] == 1, e, 0]; Array[a, 100] (* _Amiram Eldar_, Feb 21 2021 *) %o A065334 (PARI) A065334(n) = if(1==n,0,my(f = factor(n)); if(f[#f~, 1] > 3, 0, valuation(n,2))); \\ _Antti Karttunen_, Oct 09 2018 %Y A065334 Cf. A007814, A065332, A065333, A065335. %K A065334 nonn,look %O A065334 1,4 %A A065334 _Reinhard Zumkeller_, Oct 29 2001 %E A065334 Typo in formula corrected, erroneous comment removed by _Antti Karttunen_, Oct 09 2018