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 A144693 Triangle read by rows, A000012 * (3*A144328 - 2*A000012), where A000012 means a lower triangular matrix of all 1's. 2
 1, 2, 1, 3, 2, 4, 4, 3, 8, 7, 5, 4, 12, 14, 10, 6, 5, 16, 21, 20, 13, 7, 6, 20, 28, 30, 26, 16, 8, 7, 24, 35, 40, 39, 32, 19, 9, 8, 28, 42, 50, 52, 48, 38, 22, 10, 9, 32, 49, 60, 65, 64, 57, 44, 25, 11, 10, 36, 56, 70, 78, 80, 76, 66, 50, 28 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS G. C. Greubel, Rows n = 1..50 of the triangle, flattened FORMULA Sum_{k=1..n} T(n, k) = A064808(n). T(n, k) = (3*k -5 +3*[k=1])*(n-k+1). - G. C. Greubel, Oct 19 2021 EXAMPLE Partial sums by columns of the triangle (3*A144328 - 2*A000012): 1; 1, 1; 1, 1, 4; 1, 1, 4, 7; 1, 1, 4, 7, 10; ... First few rows of the triangle: 1; 2, 1 3, 2, 4; 4, 3, 8, 7; 5, 4, 12, 14, 10; 6, 5, 16, 21, 20, 13; 7, 6, 20, 28, 30, 26, 16; 8, 7, 24, 35, 40, 39, 32, 19; ... MATHEMATICA T[n_, k_]:= (3*k -5 +3*Boole[k==1])*(n-k+1); Table[T[n, k], {n, 12}, {k, n}]//Flatten (* G. C. Greubel, Oct 19 2021 *) PROG (Magma) A144693:= func< n, k | k eq 1 select n else (3*k-5)*(n-k+1) >; [A144693(n, k): k in [1..n], n in [1..12]]; // G. C. Greubel, Oct 19 2021 (Sage) def A144693(n, k): return (3*k -5 +3*bool(k==1))*(n-k+1) flatten([[A144693(n, k) for k in (1..n)] for n in (1..12)]) # G. C. Greubel, Oct 19 2021 CROSSREFS Cf. A000012, A064808, A144328. Sequence in context: A034390 A368671 A183912 * A328399 A328171 A029139 Adjacent sequences: A144690 A144691 A144692 * A144694 A144695 A144696 KEYWORD nonn,tabl AUTHOR Gary W. Adamson, Sep 19 2008 STATUS approved

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Last modified June 23 15:01 EDT 2024. Contains 373651 sequences. (Running on oeis4.)