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A073109 a(n) = Product_{p<=n, p} * Sum_{k=1..n} B(k)*C(2k,k) where B(k) is the k-th Bernoulli number and p denotes the odd primes. 0
0, 0, -7, -35, 295, 2065, -42980, -42980, 1426670, 15693370, -774856236, -10073131068, 692669409432, 692669409432, -63315621131763, -1076365559239971, 126262920264259779, 2398995485020935801, -351338708777824396629, -351338708777824396629 (list; graph; refs; listen; history; text; internal format)
OFFSET
2,3
COMMENTS
a(n) = a(n+1) for n=2, 8, 14, 20, 24, 26, 32, 34, 38, 44, 48, 50, 54, 56, 62, 64, 68, 74, 76, 80, 84, 86, 90, 92, 94, 98...it seems this is true for n=6k+2, n=10k+24, ...
LINKS
PROG
(PARI) a(n)=(1/2)*prod(i=1, n, i^isprime(i))*sum(k=1, n, bernfrac(k)*binomial(2*k, k))
CROSSREFS
Sequence in context: A096686 A165505 A165639 * A231511 A078235 A364454
KEYWORD
easy,sign
AUTHOR
Benoit Cloitre, Aug 19 2002
STATUS
approved

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Last modified July 18 00:08 EDT 2024. Contains 374377 sequences. (Running on oeis4.)