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 A169778 a(n) = ceiling(A170905/2). 2
 0, 1, 1, 1, 2, 1, 2, 3, 4, 1, 2, 3, 5, 5, 4, 7, 8, 1, 2, 3, 5, 5, 5, 9, 13, 9, 4, 7, 12, 14, 10, 16, 16, 1, 2, 3, 5, 5, 5, 9, 13, 9, 5, 9, 15, 19, 17, 21, 29, 17, 4, 7, 12, 14, 14, 22, 34, 30, 14, 16, 28, 35, 25, 35, 32, 1, 2, 3, 5, 5, 5, 9, 13, 9, 5, 9, 15, 19, 17, 21 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS The hexagon-based CA of A151723 has as symmetry group the dihedral group of order 12. Consider a one-twelfth slice; a(n) is the number of cells that are turned from OFF to ON at generation n. LINKS FORMULA A170905(n) = 2a(n) except A170905(1)=1. EXAMPLE Illustration of generations 1 through 9: .1 ..2 ...3 ..4.4 .....5 ..7.6.6 ...7...7 ..8.8.8.8 .........9 ... From Omar E. Pol, Feb 12 2013: (Start) When written as a triangle from 1, the right border gives A011782 and row lengths give A011782. 1, 1, 1,2, 1,2,3,4, 1,2,3,5,5,4,7,8, 1,2,3,5,5,5,9,13,9,4,7,12,14,10,16,16, 1,2,3,5,5,5,9,13,9,5,9,15,19,17,21,29,17,4,7,12,14,14,22,34,30,14,16,28,35,25,35,32; 1,2,3,5,5,5,9,13,9,5,9,15,19,17,21,... (End) CROSSREFS Cf. A151723, A151724, A170905. Sequence in context: A062050 A233782 A233972 * A309776 A255560 A328472 Adjacent sequences:  A169775 A169776 A169777 * A169779 A169780 A169781 KEYWORD nonn,tabf AUTHOR N. J. A. Sloane, May 08 2010 STATUS approved

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Last modified January 19 07:36 EST 2021. Contains 340267 sequences. (Running on oeis4.)