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A090813
a(n)=3*(3^prime(n)-1)*B(2*prime(n)) where prime(n)=n-th prime and B(k) denotes the k-th Bernoulli number.
0
55, 7651, 3290729563, 6818200140583, 166441513807473717727, 1702709510836284027532747, 597359613401618666812910561358019, 49136798858325589887577115786547403314116681479
OFFSET
3,1
COMMENTS
Appears to be an integer value for n=3 up to 250.
PROG
(PARI) a(n)=3*(3^prime(n)-1)*bernfrac(2*prime(n))
CROSSREFS
Sequence in context: A028471 A004708 A269500 * A145617 A105842 A113632
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Feb 11 2004
STATUS
approved