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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.

A256531 First differences of A256530.

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%I A256531 #54 Nov 15 2023 15:06:11
%S A256531 0,1,8,12,28,12,36,60,68,12,36,60,84,108,132,156,148,12,36,60,84,108,
%T A256531 132,156,180,204,228,252,276,300,324,348,308,12,36,60,84,108,132,156,
%U A256531 180,204,228,252,276,300,324,348,372,396,420,444,468,492,516,540,564,588,612,636,660,684,708,732,628,12,36,60,84,108
%N A256531 First differences of A256530.
%C A256531 Number of cells turned ON at n-th stage of cellular automaton of A256530.
%C A256531 Similar to A261695 which shares infinitely many terms.
%H A256531 Paolo Xausa, <a href="/A256531/b256531.txt">Table of n, a(n) for n = 0..8191</a>
%H A256531 N. J. A. Sloane, <a href="/wiki/Catalog_of_Toothpick_and_CA_Sequences_in_OEIS">Catalog of Toothpick and Cellular Automata Sequences in the OEIS</a>
%H A256531 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a>
%e A256531 With the positive terms written as an irregular triangle in which the row lengths are the terms of A011782 the sequence begins:
%e A256531 1;
%e A256531 8;
%e A256531 12, 28;
%e A256531 12, 36, 60, 68;
%e A256531 12, 36, 60, 84, 108, 132, 156, 148;
%e A256531 12, 36, 60, 84, 108, 132, 156, 180, 204, 228, 252, 276, 300, 324, 348, 308;
%e A256531 ...
%e A256531 The terms of the rows that start with 12 are also the initial terms of A073762, except the last term of every row, hence rows converge to A073762.
%t A256531 With[{z=7},Differences[Join[{0,0},Flatten[Array[(2^#-1)^2+12Range[0,2^(#-1)-1]^2&,z]]]]] (* Generates 2^z terms *) (* _Paolo Xausa_, Nov 15 2023, after _Omar E. Pol_ *)
%o A256531 (GW-BASIC) 10' a256531 First 2^z-1 positive terms: 20 z=6: defdbl a: for i=1 to z: for j=0 to 2^(i-1)-1: n=n+1: a(n)=(2^i-1)^2 + 3*(2*j)^2: print a(n)-a(n-1);: next j: next i: end
%Y A256531 Cf. A011782, A073762, A139251, A147582, A161411, A161415, A256530, A261695.
%K A256531 nonn,tabf
%O A256531 0,3
%A A256531 _Omar E. Pol_, Apr 21 2015