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 A257144 #14 Apr 23 2015 01:37:05
%S A257144 1,2,3,4,5,7,8,9,11,13,15,16,17,19,23,24,25,27,28,29,31,32,33,35,37,
%T A257144 40,41,43,44,45,47,49,51,53,59,60,61,63,64,65,67,69,71,73,76,77,79,81,
%U A257144 83,85,87,88,89,91,92,95,96,97,99,101,103,104,107,108,109,112,113,115,117,119,121
%N A257144 Numbers n not of the form x+y*x^2 for x>1 and y>0.
%C A257144 Number n such that (d*k+1) /= (n/d), for k>0 and each value of d, where d is a divisor >1 of n.
%t A257144 n = 71; Take[Complement[Range[n^2], DeleteDuplicates@ Sort@ Flatten@ Table[x + y x^2, {x, 2, n}, {y, 1, n}]], n] (* _Michael De Vlieger_, Apr 17 2015 *)
%Y A257144 For numbers of the form x+y*x^2 with 0<y<=10: A002378 (y=1), A014105 (y=2), A049451 (y=3), A007742 (y=4), A202803 (y=5), A049453 (y=6), A092277 (y=7), A139275 (y=8), A154517 (y=9), A055437 (y=10). - _Danny Rorabaugh_, Apr 20 2015
%K A257144 nonn
%O A257144 1,2
%A A257144 _Gionata Neri_, Apr 16 2015