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A007225 Number of distinct perforation patterns for deriving (v,b)=(n+4,n) punctured convolutional codes from (2,1).
(Formerly M2023)
0
2, 12, 52, 232, 952, 3888, 15504, 61333, 240350, 937508, 3641820, 14112560, 54587280, 210907168, 814278240, 3142611402, 12126758436, 46796872472, 180619420520, 697320058864, 2693097842512, 10405151052320, 40219629005920 (list; graph; refs; listen; history; text; internal format)
OFFSET

5,1

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=5..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+4), b=5..40); (Pab Ter)

CROSSREFS

Sequence in context: A261474 A080675 A218782 * A139046 A036359 A055703

Adjacent sequences:  A007222 A007223 A007224 * A007226 A007227 A007228

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 October 15 10:46 EDT 2019. Contains 328026 sequences. (Running on oeis4.)