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A001640 A Fielder sequence.
(Formerly M3358 N1352)
1
1, 1, 4, 9, 16, 28, 43, 73, 130, 226, 386, 660, 1132, 1947, 3349, 5753, 9878, 16966, 29147, 50074, 86020, 147764, 253829, 436036, 749041, 1286728, 2210377, 3797047, 6522681, 11204863, 19248056, 33064889, 56799857, 97572504, 167612993 (list; graph; refs; listen; history; internal format)
OFFSET

1,3

REFERENCES

Fielder, Daniel C.; Special integer sequences controlled by three parameters. Fibonacci Quart 6 1968 64-70.

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

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

LINKS

S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.

S. Plouffe, 1031 Generating Functions and Conjectures, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.

FORMULA

G.f.: x(1+3x^2+4x^3+5x^4+6x^5)/(1-x-x^3-x^4-x^5-x^6).

MAPLE

A001640:=-(1+3*z**2+4*z**3+5*z**4+6*z**5)/(-1+z+z**3+z**4+z**5+z**6); [Conjectured by S. Plouffe in his 1992 dissertation.]

PROG

(PARI) a(n)=if(n<0, 0, polcoeff(x*(1+3*x^2+4*x^3+5*x^4+6*x^5)/(1-x-x^3-x^4-x^5-x^6)+x*O(x^n), n))

CROSSREFS

Sequence in context: A137354 A113495 A110997 * A161328 A073141 A093175

Adjacent sequences:  A001637 A001638 A001639 * A001641 A001642 A001643

KEYWORD

nonn

AUTHOR

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

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Last modified February 18 00:14 EST 2012. Contains 206085 sequences.