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A286629
a(n) = (A000040(n)-1) * A002110(n).
4
2, 12, 120, 1260, 23100, 360360, 8168160, 174594420, 4908043140, 181151410440, 6016814703900, 267146572853160, 12170010541088400, 549475975930141260, 28284929999070604860, 1694636240813882325960, 111520100308944333066060, 7037302881564418258996200, 518649222371297625688019940, 39055858108868927267719077300
OFFSET
1,1
FORMULA
a(n) = A006093(n) * A002110(n) = (A000040(n)-1) * A002110(n).
a(n) = A286630(n) - A002110(n).
a(n) = A276154(A061720(n-1)).
MATHEMATICA
Table[(Prime[n] - 1) Product[Prime[k], {k, n}], {n, 100}] (* Indranil Ghosh, Jul 07 2017 *)
PROG
(Scheme) (define (A286629 n) (* (- (A000040 n) 1) (A002110 n)))
(Python)
from sympy import prime, primorial
def a002110(n): return 1 if n<1 else primorial(n)
def a(n): return (prime(n) - 1)*a002110(n)
print([a(n) for n in range(1, 21)]) # Indranil Ghosh, Jul 07 2017
(PARI) a(n) = (prime(n)-1)*prod(k=1, n, prime(k)); \\ Michel Marcus, Jul 07 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jul 07 2017
STATUS
approved