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 A383252 #21 May 11 2025 18:25:55
%S A383252 1,2,5,6,8,9,10,13,14,17,18,21,22,24,25,26,29,30,33,34,37,38,40,41,42,
%T A383252 45,46,49,50,53,54,56,57,58,61,62,65,66,69,70,72,73,74,77,78,81,82,85,
%U A383252 86,88,89,90,93,94,97,98,101,102,104,105,106,109,110,113
%N A383252 Numbers that cannot be written in the form (j+2k)^2-(j+k)^2-j^2 with j,k>0.
%C A383252 Numbers congruent to {1, 2, 5, 6, 8, 9, 10, 13, 14} mod 16.
%C A383252 Also, numbers not of the form (j+k)*(3k-j) for j,k>0.
%C A383252 These numbers do not have any pair of divisors x, y such that x+y is a multiple of 4.
%H A383252 Project Euler, <a href="https://projecteuler.net/problem=135">Problem 135: Same Differences</a>.
%o A383252 (Python)
%o A383252 isok = lambda n: (n & 15) in [1, 2, 5, 6, 8, 9, 10, 13, 14]
%o A383252 print([n for n in range(1,256) if isok(n)])
%Y A383252 Cf. A364168.
%K A383252 nonn
%O A383252 1,2
%A A383252 _Darío Clavijo_, Apr 20 2025