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A243054
a(0)=1, and for n >= 1, a(n) = p_n * A002110(n) / 2, where p_n is the n-th prime.
4
1, 2, 9, 75, 735, 12705, 195195, 4339335, 92147055, 2565568005, 93810551835, 3108687597015, 137283655493985, 6237130402307805, 281279368630905645, 14449909890829548135, 863612699645536185345, 56721430329549272852565, 3577295631461912614989735, 263253771961188946371949515
OFFSET
0,2
COMMENTS
Fixed points of A243051.
From n >= 2 onward: a(n) = the product of the first n-1 odd primes multiplied by the n-th prime.
FORMULA
a(0)=1, and for n >= 1, a(n) = A000040(n)*A002110(n)/2.
a(0)=1, a(1)=2 and for n >= 2, a(n) = A006530(A070826(n)) * A070826(n).
PROG
(Scheme) (define (A243054 n) (if (zero? n) 1 (* (/ 1 2) (A000040 n) (A002110 n))))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Antti Karttunen, May 29 2014
STATUS
approved