A237341 For k in {2,3,...,9} define a sequence as follows: a(0)=0; for n>=0, a(n+1)=a(n)+1, unless a(n) ends in k, in which case a(n+1) is obtained by replacing the last digit of a(n) with the digit(s) of k^2. This is k(4).

0, 1, 2, 3, 4, 16, 17, 18, 19, 20, 21, 22, 23, 24, 216, 217, 218, 219, 220, 221, 222, 223, 224, 2216, 2217, 2218, 2219, 2220, 2221, 2222, 2223, 2224, 22216, 22217, 22218, 22219, 22220, 22221, 22222, 22223, 22224, 222216, 222217, 222218, 222219, 222220, 222221

Offset

0,3

Links

Table of n, a(n) for n=0..46.

Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, 0, 0, 0, 0, 0, 11, 0, 0, 0, 0, 0, 0, 0, 0, -10).

Formula

G.f.: (10*x^17 +20*x^16 +30*x^15 +40*x^14 -20*x^13 -10*x^12 +10*x^10 +20*x^9 +19*x^8 +18*x^7 +17*x^6 +16*x^5 +4*x^4 +3*x^3 +2*x^2 +x)/(10*x^18 -11*x^9 +1). - Alois P. Heinz, Feb 07 2014

Crossrefs

Cf. A235498, A235499, A237341 - A237346.

Sequence in context: A113232 A095261 A066103 * A004833 A350746 A283515

Adjacent sequences: A237338 A237339 A237340 * A237342 A237343 A237344

Keyword

nonn,base,easy

Author

Vincenzo Librandi, Feb 06 2014

Extensions

Definition by N. J. A. Sloane, Feb 07 2014

Status

approved