OFFSET
0,1
LINKS
Michael De Vlieger, Table of n, a(n) for n = 0..1960
Silvana Ramaj, New Results on Cyclic Compositions and Multicompositions, Master's Thesis, Georgia Southern Univ., 2021. See p. 35.
Index entries for linear recurrences with constant coefficients, signature (2,4).
FORMULA
a(n) = 2*a(n-1) + 4*a(n-2) for n > 1; a(0) = 2, a(1) = 7.
G.f.: (2+3*x)/(1-2*x-4*x^2).
a(n) = 2^(n-1) * A000032(n+3). - Diego Rattaggi, Jun 24 2020
MATHEMATICA
LinearRecurrence[{2, 4}, {2, 7}, 30] (* Harvey P. Dale, Jan 13 2015 *)
PROG
(Magma) Z<x>:=PolynomialRing(Integers()); N<r>:=NumberField(x^2-5); S:=[ ((2+r)*(1+r)^n+(2-r)*(1-r)^n)/2: n in [0..24] ]; [ Integers()!S[j]: j in [1..#S] ]; // Klaus Brockhaus, Jul 19 2009
CROSSREFS
KEYWORD
nonn
AUTHOR
Al Hakanson (hawkuu(AT)gmail.com), Jul 13 2009
EXTENSIONS
Edited and extended beyond a(5) by Klaus Brockhaus, Jul 19 2009
STATUS
approved