OFFSET
0,2
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (6,4).
FORMULA
G.f.: (1 + x)/(1 - 6*x - 4*x^2).
a(n) = 6*a(n-1) + 4*a(n-2) with n>1, a(0) = 1, a(1) = 7.
a(n) = ((3-r)^n*(-4+r) + (3+r)^n*(4+r)) / (2*r), where r=sqrt(13). - Colin Barker, Jan 22 2017
MATHEMATICA
RecurrenceTable[{a[0] == 1, a[1] == 7, a[n] == 6 a[n - 1] + 4 a[n - 2]}, a[n], {n, 0, 25}]
LinearRecurrence[{6, 4}, {1, 7}, 30] (* Harvey P. Dale, Oct 10 2017 *)
PROG
(Magma) [n le 1 select 7^n else 6*Self(n)+4*Self(n-1): n in [0..25]]; // Bruno Berselli, Feb 03 2015
(PARI) Vec((1 + x)/(1 - 6*x - 4*x^2) + O(x^30)) \\ Colin Barker, Jan 22 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Milan Janjic, Feb 02 2015
STATUS
approved