A371645 - OEIS

A371645

a(n) = Product_{k=0..n} (2*k^2)!.

1, 2, 80640, 516287415629905920000, 135851139773030831011345707357554182190215987200000000000

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OFFSET

0,2

COMMENTS

The next term has 121 digits.

LINKS

Table of n, a(n) for n=0..4.

FORMULA

a(n) ~ c * 2^(2*n^3/3 + n^2 + 4*n/3) * Pi^(n/2) * n^(4*n^3/3 + 2*n^2 + 5*n/3 + 1/2) / exp(10*n^3/9 + n^2 + n), where c = 3.03114159524498232897099596239043047625469924617878376047699145874714076...

MATHEMATICA

Table[Product[(2*k^2)!, {k, 0, n}], {n, 0, 6}]

CROSSREFS

Cf. A255322.

Sequence in context: A195003 A071067 A321246 * A060069 A354177 A231612

Adjacent sequences: A371642 A371643 A371644 * A371646 A371647 A371648

KEYWORD

nonn

AUTHOR

Vaclav Kotesovec, Mar 31 2024

STATUS

approved