A168234 A138100(n) + A168142(n).

3, 3, 13, 13, 13, 13, 13, 13, 13, 13, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 171, 171, 171, 171, 171, 171, 171

Offset: 1

Author

Paul Curtz, Nov 21 2009

Keywords

• nonn
• less

Comments

A138100 counts upwards in blocks of 2*k^2 numbers, restarting from 1,5,21,57,.. = A166464(k-1) = (2*k+1)*(2*k^2-4*k+3)/3, k>=1.

A168142 counts downwards in blocks of 2*k^2 numbers, restarting from 2*k^2, k>=1.

In consequence, the sequence here contains 2*k^2 copies of the number 1+2*k*(1+2*k^2)/3 = 1+A035597(k), k>=1,

where the sequence A035597 is a bisection of A168380.

Crossrefs

Cf. A134984, A138725, A168208.

Extensions

Edited by R. J. Mathar, Feb 15 2010