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 A112761 #8 Feb 07 2020 08:31:02 %S A112761 0,0,1,0,0,1,0,2,0,1,1,0,2,0,1,0,3,1,0,2,0,2,1,0,3,1,0,2,1,0,4,2,1,0, %T A112761 3,1,0,0,3,2,1,0,4,2,1,0,3,2,1,5,0,0,3,2,1,0,4,2,1,1,0,4,3,2,1,5,0,0, %U A112761 3,2,1,0,0,4,3,2,6,1,1,0,4,3,2,1,5,0,0,3,2,2,1,5,0,0,4,3,2,6,1,1,0,4,3,2,1 %N A112761 Exponent of 3 (value of j) in n-th number of the form 2^i*3^j*5^k. %H A112761 Amiram Eldar, <a href="/A112761/b112761.txt">Table of n, a(n) for n = 1..10000</a> %F A112761 a(n) = A007949(A051037(n)); %F A112761 a(n) = A112759(n) - A112760(n) - A112762(n). %t A112761 IntegerExponent[#, 3] & /@ Select[Range[3000], Last @ Map[First, FactorInteger[#]] <= 5 &] (* _Amiram Eldar_, Feb 07 2020 *) %Y A112761 Cf. A007949, A022336, A022329, A051037, A112759, A112760, A112762. %K A112761 nonn %O A112761 1,8 %A A112761 _Reinhard Zumkeller_, Sep 18 2005