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A003481 a(n) = 7*a(n-1) - a(n-2) + 5.
(Formerly M2120)
4
2, 20, 143, 986, 6764, 46367, 317810, 2178308, 14930351, 102334154, 701408732, 4807526975, 32951280098, 225851433716, 1548008755919, 10610209857722, 72723460248140, 498454011879263, 3416454622906706, 23416728348467684, 160500643816367087, 1100087778366101930 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

REFERENCES

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

LINKS

T. D. Noe, Table of n, a(n) for n = 0..200

Simon Plouffe, Approximations de séries génératrices et quelques conjectures, Dissertation, Université du Québec à Montréal, 1992.

Simon Plouffe, 1031 Generating Functions and Conjectures, Université du Québec à Montréal, 1992.

John Riordan and N. J. A. Sloane, Correspondence, 1974

S. M. Tanny and M. Zuker, On a unimodal sequence of binomial coefficients, Discrete Math. 9 (1974), 79-89.

FORMULA

a(n) = Fibonacci(4(n+1))-1 = A033888(n+1)-1. - Ralf Stephan, Feb 24 2004, index corrected R. J. Mathar, Sep 18 2008

MAPLE

A003481:=(-2-4*z+z**2)/(z-1)/(z**2-7*z+1); # [Simon Plouffe in his 1992 dissertation.]

MATHEMATICA

t = {2, 20}; Do[AppendTo[t, 7*t[[-1]] - t[[-2]] + 5], {n, 2, 30}] (* T. D. Noe, Oct 07 2013 *)

CROSSREFS

Cf. A033888.

Sequence in context: A229454 A003490 A081006 * A000183 A198052 A203216

Adjacent sequences:  A003478 A003479 A003480 * A003482 A003483 A003484

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Ralf Stephan, Feb 24 2004

STATUS

approved

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Last modified October 19 20:05 EDT 2018. Contains 316378 sequences. (Running on oeis4.)