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 A130650 #6 Mar 31 2012 14:42:50 %S A130650 0,0,4,13,2,13,18,4,43,8,3,41,4,4,3,13,2,37,16,43,97,4,9,10,53,4,5,10, %T A130650 3,6,61,43,2,11,2,12,163,8,13,2,5,173,8,89,4,3,37,61,101,101,107,229, %U A130650 113 %N A130650 a(n) = smallest k such that A014612(n+1) = A014612(n) + (A014612(n) mod k), or 0 if no such k exists. %C A130650 a(n) is the "weight" of 3-almost primes. %C A130650 The decomposition of 3-almost primes into weight * level + gap is A014612(n) = a(n) * A184753(n) + A114403(n) if a(n) > 0. %H A130650 Remi Eismann, <a href="/A130650/b130650.txt">Table of n, a(n) for n=1..9999</a> %e A130650 For n = 1 we have A014612(1) = 8, A014612(2) = 12; there is no k such that 12 - 8 = 4 = (8 mod k), hence a(1) = 0. %e A130650 For n = 3 we have A014612(3) = 18, A014612(4) = 20; 4 is the smallest k such that 20 - 18 = 2 = (18 mod k), hence a(3) = 4. %e A130650 For n = 21 we have A014612(21) = 98, A014612(22) = 99; 97 is the smallest k such that 99 - 98 = 1 = (97 mod k), hence a(21) = 97. %Y A130650 Cf. A014612, A114403, A184753, A184752, A117078, A117563, A001223, A118534. %K A130650 nonn %O A130650 1,3 %A A130650 _Rémi Eismann_, Aug 16 2007 - Jan 21 2011