OFFSET
0,1
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (2,-1).
FORMULA
G.f.: (1+x)*(2+x)/(1-x)^2.
a(n) = A270700(n)/6.
a(n) = 6*n+1 = A016921(n) for n>0.
a(n) = 2*a(n-1)-a(n-2) for n>2.
E.g.f.: 1 + (1+6*x)*exp(x). - G. C. Greubel, Mar 31 2016
From Bruno Berselli and G. C. Greubel, Mar 31 2016: (Start)
a(5*m+1) = 30*m + 7 = A132231(m+1).
a(5*m+2) = 30*m + 13 = A082369(m+1).
a(5*m+3) = 30*m + 19 = A156376(m).
a(5*m+4) = 30*m + 25 = 5*A016969(m).
a(5*m+5) = 30*m + 31 = A128470(m+1). (End)
a(n) = A100764(n+3) for n >= 1. - Georg Fischer, Oct 30 2018
MATHEMATICA
Join[{2}, LinearRecurrence[{2, -1}, {7, 13}, 100]] (* G. C. Greubel, Mar 31 2016 *)
PROG
(PARI) Vec((1+x)*(2+x)/(1-x)^2 + O(x^70))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Mar 31 2016
STATUS
approved