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A055797 T(2n+4,n), array T as in A055794. 0
1, 6, 22, 64, 162, 372, 792, 1584, 3003, 5434, 9438, 15808, 25636, 40392, 62016, 93024, 136629, 196878, 278806, 388608, 533830, 723580, 968760, 1282320, 1679535, 2178306, 2799486, 3567232, 4509384 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

If Y is a 2-subset of an n-set X then, for n>=7, a(n-7) is the number of 7-subsets of X which have no exactly one element in common with Y. - Milan R. Janjic (agnus(AT)blic.net), Dec 28 2007

LINKS

Alexsandar Petojevic, The Function vM_m(s; a; z) and Some Well-Known Sequences, Journal of Integer Sequences, Vol. 5 (2002), Article 02.1.7

FORMULA

binomial(n,7)+binomial(n,5), n>=5. - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jul 24 2006

MAPLE

[seq(binomial(n, 7)+binomial(n, 5), n=5..34)]; - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jul 24 2006

MATHEMATICA

a=1; b=2; c=3; d=4; e=5; f=6; s=7; lst={s}; Do[a+=n; b+=a; c+=b; d+=c; e+=d; f+=e; s+=f; AppendTo[lst, s], {n, 6!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), May 24 2009]

CROSSREFS

Sequence in context: A166020 A120477 A053739 * A001925 A002663 A099855

Adjacent sequences:  A055794 A055795 A055796 * A055798 A055799 A055800

KEYWORD

nonn

AUTHOR

Clark Kimberling (ck6(AT)evansville.edu), May 28 2000

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Last modified February 14 03:03 EST 2012. Contains 205567 sequences.