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Search: id:A108087
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| A108087 |
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Array, read by antidiagonals, where A(n,k) = (sum_{i=0..infinity} (i+k)^n/i!)/exp(1). |
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+0 1
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| 1, 1, 1, 2, 2, 1, 5, 5, 3, 1, 15, 15, 10, 4, 1, 52, 52, 37, 17, 5, 1, 203, 203, 151, 77, 26, 6, 1, 877, 877, 674, 372, 141, 37, 7, 1, 4140, 4140, 3263, 1915, 799, 235, 50, 8, 1, 21147, 21147, 17007, 10481, 4736, 1540, 365, 65, 9, 1, 115975, 115975, 94828, 60814, 29371
(list; table; graph; listen)
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OFFSET
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0,4
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COMMENT
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The column for k=0 is A000110 (Bell or exponential numbers). The column for k=1 is A000110 starting at offset 1. The column for k=2 is A005493 (Sum_{k=0..n} k*Stirling2(n,k).). The column for k=3 is A005494 (E.g.f.: exp(3*z+exp(z)-1). From expansion of falling factorials (binomial transform of A005493)). The column for k=4 is A045379 (E.g.f.: exp(4*z+exp(z)-1).). The row for n=0 is 1's sequence, the row for n=1 is the natural numbers. The row for n=2 is A002522 (n^2 + 1.). The row for n=3 is A005491 (n^3 + 3n + 1.). The row for n=4 is A005492 (From expansion of falling factorials.).
Number of ways of placing n labeled balls into n+k boxes, where k of the boxes are labeled and the rest are indistinguishable. - Bradley Austin (artax(AT)cruzio.com), Apr 24 2006
The column for k = -1 (not shown) is A000296 (Number of partitions of an n-set into blocks of size >1. Also number of cyclically spaced (or feasible) partitions.). - Gerald McGarvey (gerald.mcgarvey(AT)comcast.net), Oct 08 2006
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REFERENCES
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F. Ruskey, Combinatorial Generation, preprint, 2001.
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LINKS
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F. Ruskey, Lexicographic Algorithms
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FORMULA
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For n> 1, A(n, k) = k^n + sum_{i=0..n-2} A086659(n, i)*k^i. (A086659 is set partitions of n containing k-1 blocks of length 1, with e.g.f: exp(x*y)*(exp(exp(x)-1-x)-1).)
A(n, k) = k * A(n-1, k) + A(n-1, k+1), A(0, k) = 1 - Bradley Austin (artax(AT)cruzio.com), Apr 24 2006
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PROGRAM
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(PARI) PARI code for printing k+1 terms of n-th row: f(n, k)=round(suminf(i=0, (i+k)^n/i!)/exp(1)) g(n, k)=for(k=0, k, print1(f(n, k), ", "))
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CROSSREFS
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Cf. A000110, A000110, A005493, A005494, A045379, A002522, A005491, A005492, A086659.
Adjacent sequences: A108084 A108085 A108086 this_sequence A108088 A108089 A108090
Sequence in context: A033184 A110488 A134379 this_sequence A123158 A133611 A010094
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KEYWORD
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nonn,tabl
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AUTHOR
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Gerald McGarvey (gerald.mcgarvey(AT)comcast.net), Jun 05 2005
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