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A302914
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Determinant of n X n matrix whose main diagonal consists of the first n 10-gonal numbers and all other elements are 1's.
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5
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1, 9, 234, 11934, 1002456, 125307000, 21803418000, 5036589558000, 1490830509168000, 550116457882992000, 247552406047346400000, 133430746859519709600000, 84861955002654535305600000, 62882708656967010661449600000, 53701833193049827104877958400000
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OFFSET
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1,2
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COMMENTS
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In general, for k > 2, these determinants for k-gonal numbers satisfies:
a(n,k) = ((k-2)/2)^(n-1) * Gamma(n) * Gamma(n + k/(k-2)) / Gamma(1 + k/(k-2)).
a(n,k) ~ 4*Pi * (k/2 - 1)^n * n^(2*n + 2/(k-2)) / (k * Gamma(k/(k-2)) * exp(2*n)).
a(n+1,k) = a(n,k) * n*((k-2)*n + k)/2.
(End)
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LINKS
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FORMULA
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a(n) = 4^(n+1) * Gamma(n) * Gamma(n + 5/4) / (5*Gamma(1/4)).
a(n) ~ Pi * 2^(2*n + 3) * n^(2*n + 1/4) / (5 * Gamma(1/4) * exp(2*n)).
a(n+1) = a(n) * n*(4*n + 5).
(End)
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EXAMPLE
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The matrix begins:
1 1 1 1 1 1 1 ...
1 10 1 1 1 1 1 ...
1 1 27 1 1 1 1 ...
1 1 1 52 1 1 1 ...
1 1 1 1 85 1 1 ...
1 1 1 1 1 126 1 ...
1 1 1 1 1 1 175 ...
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MAPLE
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d:=(i, j)->`if`(i<>j, 1, i*(4*i-3)):
seq(LinearAlgebra[Determinant](Matrix(n, d)), n=1..16);
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MATHEMATICA
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nmax = 20; Table[Det[Table[If[i == j, i*(4*i-3), 1], {i, 1, k}, {j, 1, k}]], {k, 1, nmax}] (* Vaclav Kotesovec, Apr 16 2018 *)
RecurrenceTable[{a[n+1] == a[n] * n*(4*n + 5), a[1] == 1}, a, {n, 1, 20}] (* Vaclav Kotesovec, Apr 16 2018 *)
Table[FullSimplify[4^(n+1) * Gamma[n] * Gamma[n + 5/4] / (5*Gamma[1/4])], {n, 1, 15}] (* Vaclav Kotesovec, Apr 16 2018 *)
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PROG
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(PARI) a(n) = matdet(matrix(n, n, i, j, if (i!=j, 1, i*(4*i-3)))); \\ Michel Marcus, Apr 16 2018
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CROSSREFS
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Cf. Determinant of n X n matrix whose main diagonal consists of the first n k-gonal numbers and all other elements are 1's: A000142 (k=2), A067550 (k=3), A010791 (k=4, with offset 1), A302909 (k=5), A302910 (k=6), A302911 (k=7), A302912 (k=8), A302913 (k=9), this sequence (k=10).
Cf. A007840 (permanent instead of determinant, for k=2).
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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