OFFSET
0,2
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
Paul K. Stockmeyer, The Pascal Rhombus and the Stealth Configuration, arXiv:1504.04404 [math.CO], 2015.
Index entries for linear recurrences with constant coefficients, signature (7,-14,8).
FORMULA
a(n) = 7*a(n-1)-14*a(n-2)+8*a(n-3). - Colin Barker, Jun 05 2015
G.f.: (4*x^4-4*x^3-5*x^2+3*x-1) / ((x-1)*(2*x-1)*(4*x-1)). - Colin Barker, Jun 05 2015
a(n) = (2^n)^2 + (2^n-1)^2 - (2^(n-1))^2 - 2*(2^(n-2))^2 (see (4) in arXiv link). - Michel Marcus, Jun 06 2015
MATHEMATICA
Join[{1, 4}, Table[13 4^n/8 - 2^(n + 1) + 1, {n, 2, 40}]] (* Vincenzo Librandi, Jun 06 2015 *)
LinearRecurrence[{7, -14, 8}, {1, 4, 19, 89, 385}, 30] (* Harvey P. Dale, Feb 20 2020 *)
PROG
(PARI) Vec((4*x^4-4*x^3-5*x^2+3*x-1) / ((x-1)*(2*x-1)*(4*x-1)) + O(x^100)) \\ Colin Barker, Jun 05 2015
(Magma) I:=[1, 4, 19, 89, 385]; [n le 5 select I[n] else 7*Self(n-1)-14*Self(n-2)+8*Self(n-3): n in [1..40]]; // Vincenzo Librandi, Jun 06 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Apr 14 2015
STATUS
approved