A165636 a(n) = A091137(n)/2^n.

1, 1, 3, 3, 45, 45, 945, 945, 14175, 14175, 467775, 467775, 638512875, 638512875, 1915538625, 1915538625, 488462349375, 488462349375, 194896477400625, 194896477400625, 32157918771103125, 32157918771103125, 2218896395206115625, 2218896395206115625, 3028793579456347828125, 3028793579456347828125, 9086380738369043484375

Offset

0,3

Links

Table of n, a(n) for n=0..26.

Formula

a(n+1) = a(n)* A141459(n+1).

Maple

A091137 := proc(n) local a, i, p ; a := 1 ; for i from 1 do p := ithprime(i) ; if p > n+1 then break; end if; a := a*p^floor(n/(p-1)) ; end do: a ; end proc:
A165636 := proc(n) A091137(n)/2^n ; end proc: # R. J. Mathar, Jul 07 2011

Prog

(PARI) a(n)=my(p=primes(primepi(n+1))); prod(i=1, #p, p[i]^(n\(p[i]-1)))>>n \\ Charles R Greathouse IV, Jul 07 2011

Crossrefs

Cf. A171080, A001897, A036278.

Sequence in context: A174325 A290366 A083391 * A142469 A009809 A265717

Adjacent sequences: A165633 A165634 A165635 * A165637 A165638 A165639

Keyword

nonn

Author

Paul Curtz, Sep 23 2009

Status

approved