OFFSET
1,2
COMMENTS
LINKS
Colin Barker, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (2,1,-4,1,2,-1).
FORMULA
a(2n) = A100175(2n)/2.
From Colin Barker, Aug 02 2016: (Start)
a(n) = (-1+(-1)^n+(7-3*(-1)^n)*n-6*n^2+6*n^3)/8.
a(n) = (3*n^3-3*n^2+2*n)/4 for n even.
a(n) = (3*n^3-3*n^2+5*n-1)/4 for n odd.
a(n) = 2*a(n-1)+a(n-2)-4*a(n-3)+a(n-4)+2*a(n-5)-a(n-6) for n>6.
(End)
EXAMPLE
(1/2) * ((1, 8, 30, 76, 155, 276,...) + (1, 0, 4, 0, 7, 0, 10,...)) = (1, 4, 17, 38, 81, 138, 229,...).
MATHEMATICA
LinearRecurrence[{2, 1, -4, 1, 2, -1}, {1, 4, 17, 38, 81, 138}, 50] (* Harvey P. Dale, Jun 12 2018 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Gary W. Adamson, Dec 30 2010
STATUS
approved