A102603 a(n) = 24*n + 21.

21, 45, 69, 93, 117, 141, 165, 189, 213, 237, 261, 285, 309, 333, 357, 381, 405, 429, 453, 477, 501, 525, 549, 573, 597, 621, 645, 669, 693, 717, 741, 765, 789, 813, 837, 861, 885, 909, 933, 957, 981, 1005, 1029, 1053, 1077, 1101, 1125, 1149, 1173, 1197, 1221, 1245

Offset: 0

Author

Alexandre Wajnberg, Jan 29 2005

Keywords

• easy
• nonn

Links

• Tanya Khovanova, Recursive Sequences.
• Index entries for linear recurrences with constant coefficients, signature (2,-1).

Crossrefs

Cf. A004771.

Programs

Mathematica

Range[21, 2000, 24] (* Vladimir Joseph Stephan Orlovsky, Jun 14 2011 *)
24*Range[0,60]+21 (* or *) LinearRecurrence[{2,-1},{21,45},60] (* Harvey P. Dale, Oct 06 2015 *)

PARI

a(n)=24*n+21 \\ Charles R Greathouse IV, Jun 14 2011

PARI

Vec(3*(x+7)/(x-1)^2 + O(x^52)) \\ Elmo R. Oliveira, Jul 01 2025

Formula

From Elmo R. Oliveira, Jul 01 2025: (Start)

G.f.: 3*(7 + x)/(1-x)^2.

E.g.f.: 3*(7 + 8*x)*exp(x).

a(n) = 3*A004771(n).

a(n) = 2*a(n-1) - a(n-2). (End)

Extensions

More terms from Elmo R. Oliveira, Jul 01 2025