OFFSET
1,2
COMMENTS
Also, except for the first term, sequence found by reading the line from 16, in the direction 16, 63,... in the square spiral whose vertices are the generalized decagonal numbers A074377. - Omar E. Pol, Nov 05 2012
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
FORMULA
a(n) = 16*n^2 - 33*n + 18. - R. J. Mathar, Sep 08 2008
G.f. x*(1 + 13*x + 18*x^2)/(1-x)^3. - R. J. Mathar, Oct 31 2011
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - Vincenzo Librandi, Jul 10 2012
E.g.f.: -18 + (18 - 17*x + 16*x^2)*exp(x). - G. C. Greubel, Nov 09 2019
MAPLE
seq( ((32*n-33)^2 +63)/64, n=1..40); # G. C. Greubel, Nov 09 2019
MATHEMATICA
f[n_]:= 16n^2 -33n +18; Array[f, 40] (* Robert G. Wilson v, Oct 31 2011 *)
((32*Range[50]-33)^2 +63)/64 (* G. C. Greubel, Nov 09 2019 *)
PROG
(Magma) [16*n^2-33*n+18: n in [1..40]]; // Vincenzo Librandi, Jul 10 2012
(PARI) a(n)=16*n^2-33*n+18 \\ Charles R Greathouse IV, Jun 17 2017
(Sage) [((32*n-33)^2 +63)/64 for n in (1..40)] # G. C. Greubel, Nov 09 2019
(GAP) List([1..40], n-> ((32*n-33)^2 +63)/64); # G. C. Greubel, Nov 09 2019
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vladimir Joseph Stephan Orlovsky, Sep 03 2008
STATUS
approved