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 A231625 #5 Nov 13 2013 15:04:54
%S A231625 1,2,7,8,13,14,31,32,43,44,49,50,61,62,73,74,91,92,99,115,116,121,122,
%T A231625 127,128,133,134,145,146,151,152,163,164,169,170,181,182,187,188,195,
%U A231625 211,212,219,229,230,235,236,241,242,247,248,253,254,265,266,283
%N A231625 Smallest sets of 4 consecutive deficient numbers in arithmetic progression. The initial deficient number is listed.
%H A231625 Shyam Sunder Gupta, <a href="/A231625/b231625.txt">Table of n, a(n) for n = 1..5000</a>
%e A231625 1, 2, 3, 4 is the smallest set of 4 consecutive deficient numbers in arithmetic progression so 1 is in the list.
%t A231625 DefQ[n_] := DivisorSigma[1, n] < 2 n; m = 2; z1 = 2; cd = 1; a = {}; Do[If[DefQ[n], If[n - z1 == cd, m = m + 1; If[m > 3, AppendTo[a, n - 3*cd]], m = 2; cd = n - z1]; z1 = n], {n, 3, 1000000}]; a
%Y A231625 Cf. A005100, A231623, A228961, A231624.
%K A231625 nonn
%O A231625 1,2
%A A231625 _Shyam Sunder Gupta_, Nov 11 2013