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A095661 Fifth column (m=4) of (1,3)-Pascal triangle A095660. 13
3, 13, 35, 75, 140, 238, 378, 570, 825, 1155, 1573, 2093, 2730, 3500, 4420, 5508, 6783, 8265, 9975, 11935, 14168, 16698, 19550, 22750, 26325, 30303, 34713, 39585, 44950, 50840, 57288, 64328, 71995, 80325, 89355, 99123, 109668, 121030, 133250, 146370 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

If Y is a 3-subset of an n-set X then, for n>=6, a(n-6) is the number of 4-subsets of X having at most one element in common with Y. - Milan Janjic, Nov 23 2007

Row 3 of the convolution array A213550. [Clark Kimberling, Jun 20 2012]

LINKS

Table of n, a(n) for n=0..39.

FORMULA

G.f.: (3-2*x)/(1-x)^5.

a(n)= (n+12)*binomial(n+3, 3)/4 = 3*b(n)-2*b(n-1), with b(n):=binomial(n+4, 4); cf. A000332.

a(n) = sum_{k=1..n} ( sum_{i=1..k} i*(n-k+3) ), with offset 1. - Wesley Ivan Hurt, Sep 25 2013

MAPLE

A095661:=n->(n+12)*binomial(n+3, 3)/4; seq(A095661(k), k=0..50); # Wesley Ivan Hurt, Oct 10 2013

MATHEMATICA

s1=s2=s3=s4=0; lst={}; Do[a=n+(n+2); s1+=a; s2+=s1; s3+=s2; s4+=s3; AppendTo[lst, s3/2], {n, 2, 5!}]; lst (* Vladimir Joseph Stephan Orlovsky, Apr 04 2009 *)

Table[(n+12)Binomial[n+3, 3)/4, {n, 0, 50}] (* Wesley Ivan Hurt, Oct 10 2013 *)

CROSSREFS

Partial sums of A006503.

Sequence in context: A154154 A281868 A137976 * A058214 A108480 A322187

Adjacent sequences:  A095658 A095659 A095660 * A095662 A095663 A095664

KEYWORD

nonn,easy

AUTHOR

Wolfdieter Lang, Jun 11 2004

STATUS

approved

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Last modified November 22 08:46 EST 2019. Contains 329389 sequences. (Running on oeis4.)