A278247 a(n) = least number with the same prime signature as n + (n+1)^2.

1, 2, 2, 2, 2, 2, 6, 2, 2, 2, 2, 6, 2, 6, 2, 2, 6, 6, 2, 2, 2, 6, 6, 2, 6, 2, 6, 2, 6, 2, 2, 6, 6, 6, 2, 8, 6, 2, 2, 6, 2, 12, 6, 2, 2, 2, 30, 2, 6, 2, 6, 30, 2, 2, 2, 2, 6, 6, 2, 2, 6, 30, 6, 2, 2, 2, 6, 2, 6, 2, 6, 6, 6, 6, 6, 2, 6, 6, 6, 30, 6, 6, 2, 12, 2, 2, 6, 6, 2, 6, 6, 30, 2, 2, 6, 2, 6, 6, 6, 2, 2, 30, 2, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 2, 2, 6, 30, 6, 6

Offset

0,2

Comments

Almost all terms seem to be primorials, 4848 of the first 5000, in other words, most terms of A028387 (in the same range) are squarefree.

Links

Antti Karttunen, Table of n, a(n) for n = 0..5000

Formula

a(n) = A046523(A028387(n)).

Prog

(Scheme) (define (A278247 n) (A046523 (A028387 n)))

Crossrefs

Cf. A028387, A046523.

Cf. also A278246, A278251, A278253, A278255.

Sequence in context: A051887 A139516 A225953 * A160762 A112968 A263407

Adjacent sequences: A278244 A278245 A278246 * A278248 A278249 A278250

Keyword

nonn

Author

Antti Karttunen, Nov 21 2016

Status

approved