A160648 Second differences of sequence A160644.

0, 1, 0, 0, 2, 0, 1, 4, 2, 3, 9, 6, 11, 19, 19, 27, 44, 49, 68, 98, 118, 157, 220, 268, 354, 473, 591, 765, 1003, 1254, 1609, 2071, 2597, 3293, 4192, 5236, 6594, 8308, 10345, 12926, 16163, 20031, 24886, 30890, 38123, 47081, 58102, 71381, 87704, 107643

Offset

1,5

Comments

A160644 bisects sequence A053445 which counts unrestricted partitions such that the two largest values match and that no part is less than two.

Conjecture: a(n) counts unrestricted partitions of even numbers such that

the three largest values match and that, after "222", no part is less than three.

Links

Nathaniel Johnston, Table of n, a(n) for n = 1..2500

Example

a(n) begins 0 1 0 0 2 0 1 4 2 3 9 ... and counts 222; 444,3333;
666,5553,444433,333333; 5555,44444; 6664,55543,444433;
888,6666,7773,55554,66633,444444,555333,4443333,33333333; ...

Crossrefs

Cf. A000041, A002865, A053445, A160644, A160646.

Sequence in context: A159819 A030188 A176703 * A124912 A138752 A357499

Adjacent sequences: A160645 A160646 A160647 * A160649 A160650 A160651

Keyword

easy,nonn

Author

Alford Arnold, May 25 2009

Status

approved