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 A170907 Row sums in triangle A170906. 5
 1, 4, 8, 13, 20, 28, 37, 47, 59, 73, 87, 101, 118, 137, 156, 176, 198, 223, 248, 271, 299, 328, 357, 386, 418, 454, 489, 522, 558, 598, 638, 678, 720, 766, 812, 858, 907, 956, 1004, 1048, 1104, 1161, 1217, 1268, 1325, 1386, 1446, 1505, 1567, 1635, 1703, 1765 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Total number of cells that get turned ON in the n-th 30-60-90 triangle of hexagons described in A170906. I wish I had a recurrence for this sequence! LINKS David Applegate, Table of n, a(n) for n = 1..5989 David Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata, Congressus Numerantium, Vol. 206 (2010), 157-191. [There is a typo in Theorem 6: (13) should read u(n) = 4.3^(wt(n-1)-1) for n >= 2.] N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS CROSSREFS Cf. A170906, A169757, A169758, A163862 (values at powers of 2). Sequence in context: A312218 A265382 A056738 * A143978 A071994 A023661 Adjacent sequences:  A170904 A170905 A170906 * A170908 A170909 A170910 KEYWORD nonn AUTHOR N. J. A. Sloane, Jan 24 2010 EXTENSIONS More terms from R. J. Mathar, Jan 28 2010 STATUS approved

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Last modified April 13 03:43 EDT 2021. Contains 342934 sequences. (Running on oeis4.)