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 A185730 Array by antidiagonals: T(n,k) = k*(k+1)*n*(n+1)*(k*n-n+2*k+7)/36. 2
 1, 4, 3, 10, 13, 6, 20, 34, 28, 10, 35, 70, 76, 50, 15, 56, 125, 160, 140, 80, 21, 84, 203, 290, 300, 230, 119, 28, 120, 308, 476, 550, 500, 350, 168, 36, 165, 444, 728, 910, 925, 770, 504, 228, 45, 220, 615, 1056, 1400, 1540, 1435, 1120, 696, 300, 55, 286, 825, 1470, 2040, 2380, 2401, 2100, 1560, 930, 385, 66, 364, 1078, 1980, 2850, 3480, 3724, 3528, 2940 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS This array is a member of a chain of arrays; it is the accumulation array of the array obtain by writing A125764 rectangularly - 1...3....6....10... 2...7....15...26... 3...12...27...48... and it is the weight array of A185731. (Weight and accumulation arrays are defined at A144112.) LINKS G. C. Greubel, Table of n, a(n) for the first 50 rows, flattened FORMULA T(n,k) = k*(k+1)*n*(n+1)*(k*n-n+2*k+7)/36. EXAMPLE Northwest corner: 1....4....10....20....35 3....13...34....70....125 6....28...76....160...290 10...50...140...300...550 15...80...230...500...925 MATHEMATICA f[n_, k_]:=k(1+k)n(1+n)(7+2k-n+k*n)/36; TableForm[Table[f[n, k], {n, 1, 10}, {k, 1, 15}]] Table[f[n-k+1, k], {n, 14}, {k, n, 1, -1}]//Flatten CROSSREFS Cf. A144112, A125764, A185731. Sequence in context: A081617 A103252 A065763 * A205965 A242391 A241862 Adjacent sequences:  A185727 A185728 A185729 * A185731 A185732 A185733 KEYWORD nonn,tabl AUTHOR Clark Kimberling, Feb 01 2011 STATUS approved

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Last modified August 7 23:50 EDT 2022. Contains 355995 sequences. (Running on oeis4.)