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Search: id:A052934
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| A052934 |
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A simple regular expression. |
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+0
6
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| 1, 5, 30, 180, 1080, 6480, 38880, 233280, 1399680, 8398080, 50388480, 302330880, 1813985280, 10883911680, 65303470080, 391820820480, 2350924922880, 14105549537280, 84633297223680, 507799783342080
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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With formula a(n)=(5*6^n+0^n)/6, this is the binomial transform of A083425. - Paul Barry (pbarry(AT)wit.ie), Apr 30 2003
For n>=1, a(n) is equal to the number of functions f:{1,2...,n}->{1,2,3,4,5,6} such that for a fixed x in {1,2,...,n} and a fixed y in {1,2,3,4,5,6} we have f(x)<>y. - Aleksandar M. Janjic and Milan R. Janjic (agnus(AT)blic.net), Mar 27 2007
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LINKS
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Milan Janjic, Enumerative Formulas for Some Functions on Finite Sets
INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 922
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FORMULA
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a(n) = 5*6^(n-1). G.f.: (-1+x)/(-1+6*x). Recurrence: {a(0)=1, 6*a(n)-a(n+1), a(1)=5}.
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MAPLE
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spec := [S, {S=Sequence(Prod(Sequence(Z), Union(Z, Z, Z, Z, Z)))}, unlabeled ]: seq(combstruct[count ](spec, size=n), n=0..20);
with(finance):seq(ceil(futurevalue(5, 5, n)), n=-1..18); # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 25 2009]
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MATHEMATICA
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a=1; s=a; lst={a}; Do[AppendTo[lst, a=5*s]; s=a+s, {n, 5!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Nov 10 2009]
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CROSSREFS
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Sequence in context: A105481 A094167 A051738 this_sequence A136785 A155195 A147837
Adjacent sequences: A052931 A052932 A052933 this_sequence A052935 A052936 A052937
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KEYWORD
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easy,nonn,new
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AUTHOR
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encyclopedia(AT)pommard.inria.fr, Jan 25 2000
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