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A007224 Number of distinct perforation patterns for deriving (v,b)=(n+3,n) punctured convolutional codes from (2,1).
(Formerly M1933)
0
2, 9, 38, 143, 546, 2066, 7752, 29070, 108968, 408595, 1533870, 5766243, 21710850, 81880920, 309328008, 1170524970, 4436618940, 16842720336, 64037794548, 243836217702, 929759970392, 3549992610584, 13571935767600, 51950354135888 (list; graph; refs; listen; history; text; internal format)
OFFSET

4,1

REFERENCES

G. Begin, On the enumeration of perforation patterns for punctured convolutional codes, Séries Formelles et Combinatoire Algébrique, 4th colloquium, 15-19 Juin 1992, Montréal, Université du Québec à Montréal, pp. 1-10.

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

LINKS

Table of n, a(n) for n=4..27.

MAPLE

with(numtheory):P:=proc(b, v0) local k: RETURN(add(phi(k)*(1+z^k)^(v0*(b/k)), k=divisors(b))/b): end; seq(coeff(P(b, 2), z, b+3), b=4..40); (Pab Ter)

CROSSREFS

Sequence in context: A041515 A010750 A026591 * A181339 A291265 A037489

Adjacent sequences:  A007221 A007222 A007223 * A007225 A007226 A007227

KEYWORD

nonn

AUTHOR

Simon Plouffe

EXTENSIONS

More terms from Pab Ter (pabrlos2(AT)yahoo.com), Nov 13 2005

STATUS

approved

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Last modified May 25 01:25 EDT 2019. Contains 323534 sequences. (Running on oeis4.)