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Search: id:A135338
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| A135338 |
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Triangle read by rows: row n gives coefficients C(n,j) for a Sheffer sequence (binomial-type) with raising operator -x { 1 + W[ -exp(-2) * (2+D) ] } where W is the Lambert W multi-valued function. |
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+0 2
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| 1, -1, 1, 1, -3, 1, -2, 7, -6, 1, 6, -20, 25, -10, 1, -24, 76, -105, 65, -15, 1, 120, -364, 511, -385, 140, -21, 1, -720, 2108, -2940, 2401, -1120, 266, -28, 1
(list; table; graph; listen)
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OFFSET
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1,5
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COMMENT
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The lowering (or delta) operator for these polynomials is L = -1 + exp{ 2 + W[ -exp(-2) * (2+D) ] } = sum(j >= 1) A074059(j) * D^j / j! .
The raising operator is R = -x { 1 + W[ -exp(-2) * (2+D) ] } = x { 1 + sum(j >= 1) (-1)^j * PW(j-1,-2) * D^j / j! }, where PW(j-1,x) are the polynomials of A042977.
W(x) here is W_-1 in the Monir reference and, about x = 0,
W[ -exp(-2) * (2+x) ] = -[ 2 + sum(j >= 1) (-1)^j * PW(j-1,-2) * x^j / j! ] .
From the relation between delta and raising operators for
associated binomial-type polynomials, A074059 = (1,1,2,7,34,...) and S
= (1,-PW(0,-2),PW(1,-2),-PW(2,-2),...) = (1, -1, 0, -1, -2, -13, -74,
-593, -5298, ...) form a list partition transform pair (see A133314);
i.e., S and A074059 have reciprocal e.g.f.s and satisfy mutual
recursion relations. Applying Faa di Bruno's formula to L gives other
interesting integer relations between S and A074059.
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REFERENCES
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F. Chapeau-Blondeau and A. Monir, Numerical Evaluation of the Lambert W Function and Application to Generation of Generalized Gaussian Noise With Exponent 1/2, IEEE Trans. on Signal Processing, Vol. 50, No. 9, Sept. 2002, p. 2160-2164.
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FORMULA
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The row polynomials P(n,t) = sum(j=1,...,n) C(n,j) * t^j satisfy exp[P(.,t) * x] = exp{ -t * [(1+x) * ln(1+x) - 2x] }, with P(0,t) = 1 and [ P(.,x) + P(.,y) ]^n = P(n,x+y) . See Mathworld and Wikipedia on Sheffer sequences and umbral calculus for other general formulae, including expansion theorems.
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CROSSREFS
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Cf. A134685, A135494.
Sequence in context: A134348 A074305 A151855 this_sequence A084602 A100888 A052914
Adjacent sequences: A135335 A135336 A135337 this_sequence A135339 A135340 A135341
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KEYWORD
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sign,tabl
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AUTHOR
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Tom Copeland (tcjpn(AT)msn.com), Feb 15 2008
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