A003481 a(n) = 7*a(n-1) - a(n-2) + 5. (Formerly M2120)

2, 20, 143, 986, 6764, 46367, 317810, 2178308, 14930351, 102334154, 701408732, 4807526975, 32951280098, 225851433716, 1548008755919, 10610209857722, 72723460248140, 498454011879263, 3416454622906706, 23416728348467684, 160500643816367087, 1100087778366101930

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; arXiv:0911.4975 [math.NT], 2009.

Simon Plouffe, 1031 Generating Functions, Appendix to Thesis, Montreal, 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.

Index entries for linear recurrences with constant coefficients, signature (8,-8,1).

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 *)
nxt[{a_, b_}]:={b, 7b-a+5}; NestList[nxt, {2, 20}, 30][[All, 1]] (* Harvey P. Dale, Aug 11 2019 *)

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