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 A140734 Triangle read by rows, X^n * [1,0,0,0,...]; where X = a tridiagonal matrix with (1,1,1...) in the main and subsubdiagonals and (1,2,3,...) in the subdiagonal. 1
 1, 1, 1, 1, 1, 2, 4, 4, 1, 1, 3, 9, 18, 21, 9, 1, 1, 4, 16, 48, 102, 132, 76, 16, 1, 1, 5, 25, 100, 310, 690, 970, 680, 205, 25, 1, 1, 6, 36, 180, 735, 2340, 5420, 8160, 2550, 456, 36, 1, 1, 7, 49, 294, 1491, 6195, 20195, 48440, 778315, 70245, 32571, 7602, 889, 49, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,6 LINKS EXAMPLE First few rows of the triangle are: 1; 1, 1, 1; 1, 2, 4, 4, 1; 1, 3, 9, 18, 21, 9, 1; 1, 4, 16, 48, 102, 132, 76, 16, 1; 1, 5, 25, 100, 310, 690, 970, 680, 205, 25, 1; 1, 6, 36, 180, 735, 2340, 5420, 8160, 2550, 456, 36, 1; 1, 7, 49, 294, 1491, 6195, 20195, 48440, 77315, 70245, 32571, 7602, 889, 49, 1; ... CROSSREFS Cf. A140733, A140735. Sequence in context: A057277 A258712 A238094 * A295633 A159778 A243278 Adjacent sequences:  A140731 A140732 A140733 * A140735 A140736 A140737 KEYWORD nonn,tabl AUTHOR Gary W. Adamson & Roger L. Bagula, May 25 2008 STATUS approved

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Last modified October 22 00:52 EDT 2019. Contains 328315 sequences. (Running on oeis4.)