A257246 Even bisection of A257244: a(n) = A257244(2n).

2, 3, 3, 3, 3, 5, 3, 3, 3, 5, 7, 7, 3, 3, 7, 3, 5, 3, 5, 5, 11, 3, 13, 3, 13, 5, 11, 3, 7, 3, 13, 3, 13, 3, 5, 5, 11, 23, 3, 7, 3, 7, 3, 7, 3, 31, 3, 7, 13, 3, 7, 5, 7, 3, 31, 31, 3, 13, 41, 5, 3, 7, 19, 3, 7, 41, 41, 3, 19, 7, 29, 5, 3, 13, 11, 5, 3, 19, 3, 5, 5

Offset

1,1

Links

Antti Karttunen, Table of n, a(n) for n = 1..2047

Ratio a(n)/A257245(n) plotted with OEIS Plot2-script

Formula

a(n) = A257244(2n).

a(n) = A020639(A256393(2n)). [Equally, the smallest prime factor of A256393(2n).]

Other identities and observations:

For all n >= 1, a(n) <= A257245(n).

Prog

(Scheme, alternative definitions)
(define (A257246 n) (A257244 (+ n n)))
(define (A257246 n) (A020639 (A256393 (+ n n))))

Crossrefs

Cf. A020639, A256393, A257244.

Cf. also A257245 (the other bisection), A257247 (gives the positions where both bisections have the same value).

Sequence in context: A173924 A307392 A046886 * A056206 A257245 A329245

Adjacent sequences: A257243 A257244 A257245 * A257247 A257248 A257249

Keyword

nonn

Author

Antti Karttunen, Apr 19 2015

Status

approved