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 A268432 a(n) = Pochhammer(n+1, n)/Clausen(n, 1) = A001813(n) / A160014(n, 1). 2
 1, 1, 2, 60, 56, 15120, 15840, 8648640, 17297280, 8821612800, 10158220800, 14079294028800, 474467051520, 32382376266240000, 582882772792320000, 101421602465863680000, 24659370011308032000, 415017197290314178560000, 72810034612335820800000, 2149789081963827444940800000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS FORMULA Let b(n) = Pochhammer(n+1,n)/denominator(Bernoulli(n)) then a(2*n) = b(2*n) for n >= 0 and 2*a(2*n+1) = b(2*n+1) for n >= 1 by the von Staudt-Clausen theorem. MAPLE a := proc(n) numtheory[divisors](n); map(i->i+1, %); iquo(mul(4*k+2, k in (0..n-1)), mul(k, k in select(isprime, %))) end: seq(a(n), n=0..19); PROG (Sage) def A268432(n): if n <= 1: return 1 r = rising_factorial(n+1, n)//bernoulli(n).denominator() return r if is_even(n) else r//2 [A268432(n) for n in range(20)] CROSSREFS Cf. A001813, A027642, A160014, A264437. Sequence in context: A262638 A202622 A113549 * A117482 A078511 A354770 Adjacent sequences: A268429 A268430 A268431 * A268433 A268434 A268435 KEYWORD nonn AUTHOR Peter Luschny, Feb 14 2016 STATUS approved

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Last modified March 21 16:33 EDT 2023. Contains 361408 sequences. (Running on oeis4.)