A243054 a(0)=1, and for n >= 1, a(n) = p_n * A002110(n) / 2, where p_n is the n-th prime.

1, 2, 9, 75, 735, 12705, 195195, 4339335, 92147055, 2565568005, 93810551835, 3108687597015, 137283655493985, 6237130402307805, 281279368630905645, 14449909890829548135, 863612699645536185345, 56721430329549272852565, 3577295631461912614989735, 263253771961188946371949515

Offset: 0

Author

Antti Karttunen, May 29 2014

Keywords

• nonn
• easy

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.

Crossrefs

Cf. A000040, A002110, A006530, A070826, A243051.

Programs

Scheme

(define (A243054 n) (if (zero? n) 1 (* (/ 1 2) (A000040 n) (A002110 n))))

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).