login
A012814
Take every 5th term of Padovan sequence A000931, beginning with the third term.
6
0, 1, 5, 21, 86, 351, 1432, 5842, 23833, 97229, 396655, 1618192, 6601569, 26931732, 109870576, 448227521, 1828587033, 7459895657, 30433357674, 124155792775, 506505428836, 2066337330754, 8429820731201
OFFSET
0,3
LINKS
Ulrich Brenner, Anna Hermann, and Jannik Silvanus, Constructing Depth-Optimum Circuits for Adders and AND-OR Paths, arXiv:2012.05550 [cs.DM], 2020.
FORMULA
a(n+3) = 5*a(n+2) - 4*a(n+1) + a(n).
G.f.: x/(1-5*x+4*x^2-x^3). - Colin Barker, Feb 03 2012
a(n) = A012855(n+4) - A012855(n+3).
EXAMPLE
G.f. = x + 5*x^2 + 21*x^3 + 86*x^4 + 351*x^5 + 1432*x^6 + 5842*x^7 + ...
MATHEMATICA
LinearRecurrence[{5, -4, 1}, {0, 1, 5}, 25] (* Vincenzo Librandi, Feb 03 2012 *)
PROG
(Magma) I:=[0, 1, 5 ]; [n le 3 select I[n] else 5*Self(n-1)-4*Self(n-2)+Self(n-3): n in [1..40]]; // Vincenzo Librandi, Feb 03 2012
CROSSREFS
Sequence in context: A097113 A368345 A265939 * A039919 A322875 A292494
KEYWORD
nonn,easy
EXTENSIONS
Initial term 0 added by Colin Barker, Feb 03 2012
STATUS
approved