OFFSET
0,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..10000
Tanya Khovanova, Recursive Sequences
Index entries for linear recurrences with constant coefficients, signature (2,-1).
FORMULA
a(n) = 50*n + 20.
From Colin Barker, Jun 27 2012: (Start)
a(n) = 2*a(n-1) - a(n-2).
G.f.: 10*(2+3*x)/(1-x)^2. (End)
E.g.f.: 10*(2+5*x)*exp(x). - G. C. Greubel, Sep 06 2019
EXAMPLE
20 is sum of 0, 2, 4, 6, 8;
70 is sum of 10, 12, 14, 16, 18;
120 is sum of 20, 22, 24, 26, 28; etc.
MAPLE
seq(10*(2+5*n), n=0..50); # G. C. Greubel, Sep 06 2019
MATHEMATICA
50Range[50]-30 (* Harvey P. Dale, Mar 06 2011 *)
PROG
(Magma) [20+50*n: n in [0..50]]; // Vincenzo Librandi, Aug 12 2011
(PARI) vector(50, n, 10*(5*n-3)) \\ G. C. Greubel, Sep 06 2019
(Sage) [10*(2+5*n) for n in (0..50)] # G. C. Greubel, Sep 06 2019
(GAP) List([0..50], n-> 10*(2+5*n)); # G. C. Greubel, Sep 06 2019
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Odimar Fabeny, Feb 13 2000
EXTENSIONS
More terms from James A. Sellers, Feb 22 2000
STATUS
approved