A171246 Triangle read by rows: T(n,k) = 1 + floor(n!/2^((k - n/2)^2 + 1)).
1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 7, 13, 7, 1, 1, 13, 51, 51, 13, 1, 1, 23, 181, 361, 181, 23, 1, 1, 34, 530, 2120, 2120, 530, 34, 1, 1, 40, 1261, 10081, 20161, 10081, 1261, 40, 1, 1, 38, 2384, 38144, 152573, 152573, 38144, 2384, 38, 1
Offset: 0
Examples
Triangle begins as: 1; 1, 1; 1, 2, 1; 1, 3, 3, 1; 1, 7, 13, 7, 1; 1, 13, 51, 51, 13, 1; 1, 23, 181, 361, 181, 23, 1; 1, 34, 530, 2120, 2120, 530, 34, 1;
Links
- G. C. Greubel, Rows n = 0..100 of triangle, flattened
- Philippe Flajolet and Robert Sedgewick, Analytic Combinatorics, Cambridge Univ. Press, 2009, page 695.
Crossrefs
Cf. A171229.
Programs
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Magma
[[1 +Floor(Factorial(n)/2^((k - n/2)^2 +1)): k in [0..n]]: n in [0..10]]; // G. C. Greubel, Apr 11 2019
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Mathematica
T[n_, k_]:= 1 +Floor[n!*2^(-(k-n/2)^2 -1)]; Table[T[n, k], {n,0,10}, {k,0,n}]//Flatten
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PARI
{T(n,k) = 1 + floor(n!/2^((k - n/2)^2 +1))}; \\ G. C. Greubel, Apr 11 2019
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Sage
[[1 + floor(factorial(n)/2^((k-n/2)^2 +1)) for k in (0..n)] for n in (0..10)] # G. C. Greubel, Apr 11 2019
Formula
T(n,k) = 1 + floor(n!/2^((k - n/2)^2 +1)).
Extensions
Edited by G. C. Greubel, Apr 11 2019
Comments