A253550 Shift one instance of the largest prime one step towards larger primes: a(1) = 1, for n>1: a(n) = (n / prime(g)) * prime(g+1), where g = A061395(n), index of the greatest prime dividing n.

1, 3, 5, 6, 7, 10, 11, 12, 15, 14, 13, 20, 17, 22, 21, 24, 19, 30, 23, 28, 33, 26, 29, 40, 35, 34, 45, 44, 31, 42, 37, 48, 39, 38, 55, 60, 41, 46, 51, 56, 43, 66, 47, 52, 63, 58, 53, 80, 77, 70, 57, 68, 59, 90, 65, 88, 69, 62, 61, 84, 67, 74, 99, 96, 85, 78, 71, 76, 87, 110, 73, 120, 79, 82, 105, 92, 91, 102, 83, 112, 135, 86, 89

Offset: 1

Author

Antti Karttunen, Jan 03 2015

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10000

Crossrefs

Inverse: A252462.

Cf. A102750 (same terms, but with 2 instead of 1, sorted into ascending order).

Cf. A003961, A052126, A065091, A061395, A122111, A253553, A253554, A253560, A253563, A253565.

Programs

Scheme

(define (A253550 n) (if (= 1 n) n (* (A065091 (A061395 n)) (A052126 n))))

Formula

a(1) = 1; for n>1: a(n) = A065091(A061395(n)) * A052126(n).

Other identities. For all n >= 1:

A252462(a(n)) = n. [A252462 works as an inverse function for this injection.]

a(n) <= A253560(n).