A069505 a(1) = 1; a(n) = smallest palindromic number of the form k*a(n-1) + 1 with k > 1.

1, 3, 7, 22, 111, 1111, 11111, 111111, 1111111, 11111111, 111111111, 1111111111, 11111111111, 111111111111, 1111111111111, 11111111111111, 111111111111111, 1111111111111111, 11111111111111111, 111111111111111111

Offset

0,2

Links

Table of n, a(n) for n=0..19.

Index entries for linear recurrences with constant coefficients, signature (11, -10).

Formula

a(n) = (10^(n-2) - 1)/9 for n > 4.

G.f.: (110*x^5 - 61*x^4 - 25*x^3 - 16*x^2 - 8*x + 1)/(10*x-1)/(x-1). - Maksym Voznyy (voznyy(AT)mail.ru), Jan 10 2008

Maple

A069505:=seriestolist(taylor((1+110*x^5-61*x^4-25*x^3-16*x^2-8*x)/(10*x-1)/(x-1), x, 20)); # Maksym Voznyy (voznyy(AT)mail.ru), Jan 10 2008

Crossrefs

Cf. A069506, A069507, A069508, A069509, A069510.

Sequence in context: A364627 A082271 A229438 * A363544 A373661 A355075

Adjacent sequences: A069502 A069503 A069504 * A069506 A069507 A069508

Keyword

nonn,base

Author

Amarnath Murthy, Mar 30 2002

Extensions

More terms from Patrick De Geest, Jun 11 2003

Status

approved