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A005405 Number of protruded partitions of n with largest part at most 4.
(Formerly M2565)
+0
1
1, 3, 6, 13, 24, 47, 86, 159, 285, 509, 895, 1565, 2708, 4660, 7964, 13543, 22912, 38604, 64785, 108356, 180661, 300384, 498183, 824365, 1361302, 2243799, 3692159, 6066161, 9952786, 16309055, 26694132, 43646685, 71297770, 116366274 (list; graph; listen)
OFFSET

1,2

REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

R. P. Stanley, A Fibonacci lattice, Fib. Quart., 13 (1975), 215-232.

R. P. Stanley, Ordered structures and partitions, Memoirs of the Amer. Math. Soc., no. 119 (1972).

FORMULA

G.f. = (1-x)^4/Product(1-x-x^i+x^(1+2*i), i=1..4)-1. - Emeric Deutsch (deutsch(AT)duke.poly.edu), Dec 19 2004

MAPLE

G:=(1-x)^4/Product(1-x-x^i+x^(1+2*i), i=1..4)-1: Gser:=series(G, x=0, 39): seq(coeff(Gser, x^n), n=1..37); (Deutsch)

CROSSREFS

Adjacent sequences: A005402 A005403 A005404 this_sequence A005406 A005407 A005408

Sequence in context: A061567 A018081 A001452 this_sequence A000219 A027999 A005196

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

EXTENSIONS

More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Dec 19 2004

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Last modified November 8 07:45 EST 2009. Contains 166143 sequences.


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