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A164845 3+5*n+5*n^2/2+n^3/2. +0
2
3, 11, 27, 54, 95, 153, 231, 332, 459, 615, 803, 1026, 1287, 1589, 1935, 2328, 2771, 3267, 3819, 4430, 5103, 5841, 6647, 7524, 8475, 9503, 10611, 11802, 13079, 14445, 15903, 17456, 19107, 20859, 22715, 24678, 26751, 28937, 31239, 33660, 36203, 38871 (list; graph; listen)
OFFSET

0,1

COMMENT

Row sums of the triangle defined by non-interrupted runs in A080036.

If the sequence of integers is split at positions defined by A000124 we obtain

A080036. Its runs of consecutive integers can be placed into rows of a triangle:

3;

5,6;

8,9,10;

12,13,14,15;

17,18,19,20,21;

The a(n) are the row sums of this triangle.

The a(n) are also the binomial transform of the quasi-finite sequence 3, 8, 8, 3, 0 (0 continued).

An associated integer sequence could be defined by a(n)/A026741(n+1) = 3, 11, 9, 27,...

LINKS

Index to entries for recurrences with constant coefficients.

FORMULA

a(n) = A162607(n+3)+n.

First differences: a(n+1)-a(n)=A104249(n+2), i.e., a(n)=a(n-1)+3*n^2/2+7n/2+3.

Second differences: a(n+2)-2*a(n+1)+a(n)=A016789(n+2).

a(n)=2a(n-1)-a(n-2)+3*n+5 , n>1.

a(n)=3a(n-1)-3a(n-2)+a(n-3)+3, n>2.

a(n)=4a(n-1)-6a(n-2)+4a(n-3)-a(n-4), n>3.

G.f.: (3-x+x^2)/(x-1)^4.

CROSSREFS

Cf. A135278.

Sequence in context: A101612 A123928 A164897 this_sequence A024194 A011941 A033960

Adjacent sequences: A164842 A164843 A164844 this_sequence A164846 A164847 A164848

KEYWORD

nonn

AUTHOR

Paul Curtz (bpcrtz(AT)free.fr), Aug 28 2009

EXTENSIONS

Edited and extended by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 31 2009

Corrected typo in recurrence, observed by P Curtz - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 25 2009

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Last modified December 7 08:40 EST 2009. Contains 170430 sequences.


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