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A116382 Riordan array (1/sqrt(1-4x^2),(1-2x^2*c(x^2))(x^2*c(x^2))/(x(1-x-x^2*c(x^2))) where c(x) is the g.f. of A000108. 13
1, 0, 1, 2, 1, 1, 0, 3, 2, 1, 6, 4, 5, 3, 1, 0, 10, 10, 8, 4, 1, 20, 15, 21, 19, 12, 5, 1, 0, 35, 42, 42, 32, 17, 6, 1, 70, 56, 84, 92, 77, 50, 23, 7, 1, 0, 126, 168, 192, 180, 131, 74, 30, 8, 1, 252, 210, 330, 405, 400, 326, 210, 105, 38, 9, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

Row sums are A116383. Diagonal sums are A116384. First column has e.g.f. Bessel_I(0,2x) (A000984 with interpolated zeros). Second column has e.g.f. Bessel_I(1,2x)+Bessel_I(2,2x) (A037952). Third column has e.g.f. Bessel_I(2,2x)+2*Bessel_I(3,2x)+Bessel_I(4,2x) (A116385). A binomial-Bessel triangle: column k has e.g.f. sum{j=0..k, C(k,j)*Bessel_I(k+j,2x)}.

LINKS

Table of n, a(n) for n=0..65.

FORMULA

Riordan array (1/sqrt(1-4x^2), sqrt(1-4x^2)(1-sqrt(1-4x^2))/(x-2x^2+x*sqrt(1-4x^2))); Number triangle T(n,k)=sum{j=0..n, (-1)^(n-j)*C(n,j)*sum{i=0..j, C(j,i-k)C(i,j-i)}}.

EXAMPLE

Triangle begins

1,

0, 1,

2, 1, 1,

0, 3, 2, 1,

6, 4, 5, 3, 1,

0, 10, 10, 8, 4, 1,

20, 15, 21, 19, 12, 5, 1,

0, 35, 42, 42, 32, 17, 6, 1,

70, 56, 84, 92, 77, 50, 23, 7, 1,

0, 126, 168, 192, 180, 131, 74, 30, 8, 1,

252, 210, 330, 405, 400, 326, 210, 105, 38, 9, 1

MATHEMATICA

T[n_, k_] := Sum[(-1)^(n-j)*Binomial[n, j]*Sum[Binomial[j, i-k]*Binomial[i, j-i], {i, 0, j}], {j, 0, n}];

Table[T[n, k], {n, 0, 10}, {k, 0, n}] // Flatten (* Jean-Fran├žois Alcover, Jan 24 2018 *)

CROSSREFS

Sequence in context: A288166 A126258 A235501 * A050606 A277721 A023416

Adjacent sequences:  A116379 A116380 A116381 * A116383 A116384 A116385

KEYWORD

easy,nonn,tabl

AUTHOR

Paul Barry, Feb 12 2006

STATUS

approved

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Last modified February 21 15:34 EST 2019. Contains 320374 sequences. (Running on oeis4.)