A249734 - OEIS

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A249734

Even bisection of A003961: Replace in 2n each prime factor p(k) with prime p(k+1).

7

3, 9, 15, 27, 21, 45, 33, 81, 75, 63, 39, 135, 51, 99, 105, 243, 57, 225, 69, 189, 165, 117, 87, 405, 147, 153, 375, 297, 93, 315, 111, 729, 195, 171, 231, 675, 123, 207, 255, 567, 129, 495, 141, 351, 525, 261, 159, 1215, 363, 441, 285, 459, 177, 1125, 273, 891, 345, 279, 183, 945, 201, 333, 825, 2187, 357, 585, 213, 513, 435, 693, 219, 2025, 237, 369

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OFFSET

1,1

LINKS

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

FORMULA

a(n) = A003961(2*n).

a(n) = 3 * A003961(n).

a(n) = A064989(A249827(n)).

a(n) = A003961(A243501(A064216(n))).

a(n) = A003961(A243502(A048673(n))).

a(n) = A016945(A048673(n)-1). [Permutation of A016945, 6n+3.]

Other identities. For all n >= 1:

a(A000079(n-1)) = A000244(n). [Maps each 2^n to 3^(n+1).]

PROG

(Scheme, two alternative definitions)

(define (A249734 n) (A003961 (+ n n)))

(define (A249734 n) (* 3 (A003961 n)))

CROSSREFS

Row 2 of A246278.

Cf. A249735 (the other bisection of A003961).

Cf. A016945, A048673, A064216, A064989, A249827, A243501, A243502.

Cf. also A000079, A000244.

Sequence in context: A055927 A316261 A354958 * A319316 A087031 A089632

Adjacent sequences: A249731 A249732 A249733 * A249735 A249736 A249737

KEYWORD

nonn

AUTHOR

Antti Karttunen, Nov 23 2014

STATUS

approved