The On-Line Encyclopedia of Integer Sequences (OEIS)

A160646 revision #6

A160646

First differences of A160644.

0, 1, 1, 1, 3, 3, 4, 8, 10, 13, 22, 28, 39, 58, 77, 104, 148, 197, 265, 363, 481, 638, 858, 1126, 1480, 1953, 2544, 3309, 4312, 5566, 7175, 9246, 11843, 15136, 19328, 24564, 31158, 39466, 49811, 62737, 78900, 98931, 123817, 154707, 192830, 239911, 298013

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OFFSET

1,5

COMMENTS

Second differences count a subset of unrestricted partitions; cf. A160648.

LINKS

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

EXAMPLE

A160644 begins 1, 1, 2, 3, 4, 7, 10, 14, 22, 32, 45, 67, 95, 134, 192, ... so a(n) begins 0, 1, 1, 1, 3, 3, 4, 8, 10, 13, 22, 28, 39, 58, ...

CROSSREFS

Cf. A000041, A002685, A053445, A160644, A160648.

Sequence in context: A285445 A327745 A155822 * A019466 A111573 A049854

Adjacent sequences: A160643 A160644 A160645 * A160647 A160648 A160649

KEYWORD

easy,nonn

AUTHOR

Alford Arnold (Alford1940(AT)aol.com), May 24 2009

STATUS

approved