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 A171608 Triangle by columns, T(n,k); (...n, (n+1)) preceded by (n-1) zeros, as an infinite lower triangular matrix 5
 1, 2, 0, 0, 2, 0, 0, 3, 0, 0, 0, 0, 3, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Let the triangle = M as an infinite lower triangular matrix. . M * (1, 2, 3,...) = A002620: (1, 2 4, 6, 9, 12, 16, 20,...) M * (1, 3, 5,...) = A084265: (1, 2, 6, 9, 15, 20, 28, 35,...) M * (1, 3, 6,...) = A028724: (1, 2, 6, 9, 18, 24, 40, 50, ...) Lim_{n->inf.} M^n = A171609: (1, 2, 4, 6, 12, 16, 24, 30, ...) LINKS FORMULA Triangle by columns, T(n,k); (...n, (n+1)) preceded by (n-1) zeros, as an infinite lower triangular matrix EXAMPLE First few rows of the triangle = 1; 2, 0; 0, 2, 0; 0, 3, 0, 0; 0, 0, 3, 0, 0; 0, 0, 4, 0, 0, 0; 0, 0, 0, 4, 0, 0, 0; 0, 0, 0, 5, 0, 0, 0, 0; 0, 0, 0, 0, 5, 0, 0, 0, 0; 0, 0, 0, 0, 6, 0, 0, 0, 0, 0; 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0; 0, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0; 0, 0, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0; 0, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 0; 0, 0, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 0; 0, 0, 0, 0, 0, 0, 0, 9, 0, 0, 0, 0, 0, 0, 0, 0; ... CROSSREFS Cf. A002620, A084265, A028724, A171608 Sequence in context: A216921 A280285 A033719 * A307985 A024164 A138805 Adjacent sequences:  A171605 A171606 A171607 * A171609 A171610 A171611 KEYWORD nonn,tabl AUTHOR Gary W. Adamson, Dec 12 2009 STATUS approved

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Last modified June 16 13:25 EDT 2019. Contains 324152 sequences. (Running on oeis4.)