A167573 a(n) = 20*n^2 + 3.

23, 83, 183, 323, 503, 723, 983, 1283, 1623, 2003, 2423, 2883, 3383, 3923, 4503, 5123, 5783, 6483, 7223, 8003, 8823, 9683, 10583, 11523, 12503, 13523, 14583, 15683, 16823, 18003, 19223, 20483, 21783, 23123, 24503, 25923, 27383, 28883, 30423, 32003, 33623, 35283

Offset: 1

Author

Johannes W. Meijer, Nov 10 2009

Keywords

• easy
• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 1..1000
• Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

Crossrefs

Equals the third row of the ED3 array A167572.

Programs

Mathematica

Table[20*n^2 + 3, {n, 1, 100}] (* or *) LinearRecurrence[{3,-3,1},{23, 83, 183}, 100] (* G. C. Greubel, Jun 16 2016 *)

PARI

a(n)=20*n^2+3 \\ Charles R Greathouse IV, Jun 17 2017

Formula

a(n) = 20*n^2 + 3.

G.f.: z*(3*z^2 + 14*z + 23)/(1-z)^3. [Corrected by Elmo R. Oliveira, May 31 2025]

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n > 3. - G. C. Greubel, Jun 16 2016

E.g.f.: -3 + (3 + 20*x + 20*x^2)*exp(x). - Elmo R. Oliveira, May 31 2025