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 A137680 Triangle read by rows, T(n,k) = T(n-1, k-1) - T(n-k, k-1); with leftmost term in each row = sum of all previous terms. 3
 1, 1, 1, 3, 0, 1, 7, 2, 0, 1, 17, 4, 1, 0, 1, 40, 10, 4, 1, 0, 1, 96, 23, 8, 3, 1, 0, 1, 228, 56, 19, 8, 3, 1, 0, 1, 544, 132, 46, 18, 7, 3, 1, 0, 1, 1296, 316, 109, 42, 18, 7, 3, 1, 0, 1, 3089, 752, 260, 101, 41, 17, 7, 3, 1, 0, 1, 7361, 1793, 620, 241, 98, 41, 17, 7, 3, 1, 0, 1, 17544 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS A variation of the same sequence = column 2 of the triangle: (1, 0, 2, 4, 10, 23, 56, 132,...) = first difference row of column 1. Left border of the triangle = A137682. Left column starting (1, 3,...) = INVERT transform of A160096. [From Gary W. Adamson, May 01 2009] LINKS EXAMPLE First few rows of the triangle are: 1; 1, 1; 3, 0, 1; 7, 2, 0, 1; 17, 4, 1, 0, 1; 40, 10, 4, 1, 0, 1; 96, 23, 8, 3, 1, 0, 1; 228, 56, 19, 8, 3, 1, 0, 1; 544, 132, 46, 18, 7, 3, 1, 0, 1; 1296, 316, 109, 42, 18, 7, 3, 1, 0, 1; 3089, 752, 260, 101, 41, 17, 7, 3, 1, 0, 1; ... MAPLE A137680 := proc(n, k)     if k < 1 or k > n then         0 ;     elif n = 1 then         1;     elif k = 1 then         add(add(procname(r, j), j=1..r), r=1..n-1) ;     else         procname(n-1, k-1)-procname(n-k, k-1) ;     end if; end proc: # R. J. Mathar, Aug 12 2012 CROSSREFS Cf. A137681 (row sums), A137682. A160096 [From Gary W. Adamson, May 01 2009] Sequence in context: A297786 A214407 A298668 * A248722 A201663 A199606 Adjacent sequences:  A137677 A137678 A137679 * A137681 A137682 A137683 KEYWORD nonn,tabl AUTHOR Gary W. Adamson, Feb 05 2008 STATUS approved

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Last modified July 17 17:14 EDT 2019. Contains 325107 sequences. (Running on oeis4.)