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

Author

Vincenzo Librandi, Feb 06 2014

Keywords

• nonn
• base
• easy

Links

• 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).

Crossrefs

Cf. A235498, A235499, A237341 - A237346.

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

Extensions

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