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

Author

Alford Arnold, May 25 2009

Keywords

• easy
• nonn

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.

Examples

			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; ...
		

Links

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

Crossrefs

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