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 A100591 #3 Mar 30 2012 18:40:21 %S A100591 1,4,7,10,35,25,49,61,121,140,211,268,224,392,472,517,565,529,707, %T A100591 1006,1039,994,1213,989,1274,1717,1769,1822,2047,2272,2419,2573,2642, %U A100591 3029,3149,3152,3848,3359,4199,4019,4307,4847,5027,4877,5492,6077 %N A100591 Least positive integer that can be represented as sum of semiprime and a triangular number in exactly n ways. Triangular numbers include t(0)=0 and (1)=1. %C A100591 Computed by Ray Chandler. %F A100591 a(n) = min(i such that i = A001358(j) + A000217(k) in n ways). %e A100591 a(0) = 1 because 1 is the smallest positive integer that cannot be represented as sum of semiprime and a triangular number (since 4 is the smallest semiprime). a(1) = 4 because 4 is the smallest such sum, namely semiprime(1)=4 + t(0)=0. Similarly a(2) = 7 because 7 = 4 + 3 and 7 = 6 + 1, where 4 and 6 are semiprimes, 3 and 1 are triangular. %Y A100591 Cf. A000217, A001358, A076768, A100570. %K A100591 easy,nonn %O A100591 0,2 %A A100591 _Jonathan Vos Post_, Nov 30 2004