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 A256260 Total number of ON states after n generations of a cellular automaton-like on the square grid. 8
 1, 5, 9, 21, 25, 37, 57, 85, 89, 101, 121, 149, 169, 213, 281, 341, 345, 357, 377, 405, 425, 469, 537, 597, 617, 661, 729, 821, 937, 1077, 1241, 1365, 1369, 1381, 1401, 1429, 1449, 1493, 1561, 1621, 1641, 1685, 1753, 1845, 1961, 2101, 2265, 2389, 2409, 2453, 2521, 2613, 2729, 2869, 3033, 3221, 3433, 3669, 3929, 4213, 4521, 4853, 5209, 5461 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS First differs from A169707 at a(28). Compare A169707. It appears that both sequences share infinitely many terms, for example: a(1)..a(27), a(31)..a(43), a(47)..a(51), etc. See also the conjecture in the Example section. The main entry for this sequence is A256263. A256261 gives the number of cells turned ON at n-th stage. LINKS N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS FORMULA a(n) = 1 + 4*A256264(n-1). EXAMPLE Written as an irregular triangle T(j,k), k>=1, in which the row lengths are the terms of A011782, the sequence begins: 1; 5; 9,   21; 25,  37, 57, 85; 89, 101,121,149,169,213,281,341; 345,357,377,405,425,469,537,597,617,661,729,821,937,1077,1241,1365; ... The right border gives the positive terms of A002450. It appears that this triangle at least shares with the triangles from the following sequences; A147562, A162795, A169707, A255366, A256250, the positive elements of the columns k, if k is a power of 2. CROSSREFS Cf. A002450, A139250, A147562, A162795, A169707, A255264, A255366, A256250, A256258, A256261, A256263, A256264, A256265. Sequence in context: A255366 A269522 A169707 * A256250 A256138 A246335 Adjacent sequences:  A256257 A256258 A256259 * A256261 A256262 A256263 KEYWORD nonn,look AUTHOR Omar E. Pol, Mar 28 2015 STATUS approved

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Last modified December 15 00:30 EST 2019. Contains 329988 sequences. (Running on oeis4.)