A086947 Numbers k such that Reverse(k+9) = 3.

21, 291, 2991, 29991, 299991, 2999991, 29999991, 299999991, 2999999991, 29999999991, 299999999991, 2999999999991, 29999999999991, 299999999999991, 2999999999999991, 29999999999999991, 299999999999999991

Offset

1,1

Comments

Reverse(a(n)) = A086948(n).

If k is in this sequence then Reverse(k) = (2/3)*k - 2. Also A101703 is the sequence of all numbers k such that Reverse(k) = (2/3)*k - 2. So this sequence is a subsequence of A101703. - Farideh Firoozbakht, Dec 30 2004

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..300

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

Formula

a(n) = 3*(10^n - 3).

From Chai Wah Wu, Aug 01 2020: (Start)

a(n) = 11*a(n-1) - 10*a(n-2) for n > 2.

G.f.: x*(60*x + 21)/((x - 1)*(10*x - 1)). (End)

Mathematica

Table[3*(10^n-3), {n, 17}]
Table[FromDigits[PadRight[{3}, n, 0]], {n, 2, 20}]-9 (* Harvey P. Dale, Nov 27 2012 *)

Prog

(Magma) [3*(10^n-3): n in [1..25] ]; // Vincenzo Librandi, Aug 22 2011

Crossrefs

Cf. A085331, A086948, A101700, A101703.

Sequence in context: A183731 A101703 A102018 * A230768 A230021 A101700

Adjacent sequences: A086944 A086945 A086946 * A086948 A086949 A086950

Keyword

nonn,base

Author

Ray Chandler, Jul 24 2003

Status

approved