A249735 Odd bisection of A003961: Replace in 2n-1 each prime factor p(k) with prime p(k+1).

1, 5, 7, 11, 25, 13, 17, 35, 19, 23, 55, 29, 49, 125, 31, 37, 65, 77, 41, 85, 43, 47, 175, 53, 121, 95, 59, 91, 115, 61, 67, 275, 119, 71, 145, 73, 79, 245, 143, 83, 625, 89, 133, 155, 97, 187, 185, 161, 101, 325, 103, 107, 385, 109, 113, 205, 127, 203, 425, 209, 169, 215, 343, 131, 235, 137, 253, 875, 139, 149, 265, 221, 217, 605, 151

Offset: 1

Author

Antti Karttunen, Nov 23 2014

Keywords

• nonn

Comments

This has the same terms as A007310 (Numbers congruent to 1 or 5 mod 6), but in different order. Apart from 1, they are the numbers that occur below the first two rows of arrays like A246278 and A083221 (A083140).

Links

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

Crossrefs

Cf. A249734 (the other bisection of A003961).

Cf. also A007310 (A038179), A249746.

Programs

Scheme

(define (A249735 n) (A003961 (+ n n -1)))

Formula

a(n) = A003961(2n - 1).

a(n) = A007310(A249746(n)). [Permutation of A007310, Numbers congruent to 1 or 5 mod 6.]

Other identities. For all n >= 1:

A007310(n) = a(A249745(n)).

A246277(5*a(A048673(n))) = n.

A246277(5*a(n)) = A064216(n).