A155859 a(n) = (1/162)*(61*10^n + 18*n + 20).

4, 38, 377, 3766, 37655, 376544, 3765433, 37654322, 376543211, 3765432100, 37654320989, 376543209878, 3765432098767, 37654320987656, 376543209876545, 3765432098765434, 37654320987654323, 376543209876543212, 3765432098765432101, 37654320987654320990

Offset

1,1

Comments

First prime: a(19) = 3765432098765432101. Next prime: a(271) = 3*10^270 + 765432098*(10^(9*29)-1)*10^9/(10^9-1) + 765432129. - Bruno Berselli, Oct 15 2013

Links

G. C. Greubel, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (12,-21,10).

Formula

from Bruno Berselli, Oct 15 2013: (Start)

G.f.: x*(4 -10*x +5*x^2)/((1-10*x)*(1-x)^2).

a(n) = 12*a(n-1) -21*a(n-2) +10*a(n-3). (End)

E.g.f.: (1/162)*(-81 + 2*(10 + 9*x)*exp(x) + 61*exp(10*x)). - G. C. Greubel, Jun 04 2021

Mathematica

Table[(1/162)*(61*10^n +18*n +20), {n, 20}] (* Bruno Berselli, Oct 15 2013 *)

Prog

(PARI) a(n) = (1/162)*(61*10^n + 18*n + 20); \\ Michel Marcus, Oct 15 2013
(Magma) [(1/162)*(61*10^n+18*n+20): n in [1..20]]; // Bruno Berselli, Oct 15 2013
(Sage) [(1/162)*(61*10^n +18*n +20) for n in (1..20)] # G. C. Greubel, Jun 04 2021

Crossrefs

Sequence in context: A240378 A220807 A221021 * A220543 A220748 A192947

Adjacent sequences: A155856 A155857 A155858 * A155860 A155861 A155862

Keyword

nonn,easy,changed

Author

Zak Seidov, Jan 29 2009

Status

approved