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

1,2

Links

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

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).

Prog

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

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.

Sequence in context: A028730 A028747 A136806 * A295307 A073803 A336353

Adjacent sequences: A253547 A253548 A253549 * A253551 A253552 A253553

Keyword

nonn

Author

Antti Karttunen, Jan 03 2015

Status

approved