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A165636
a(n) = A091137(n)/2^n.
2
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
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
KEYWORD
nonn
AUTHOR
Paul Curtz, Sep 23 2009
STATUS
approved