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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).
9
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
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
KEYWORD
nonn,base,easy
AUTHOR
Vincenzo Librandi, Feb 06 2014
EXTENSIONS
Definition by N. J. A. Sloane, Feb 07 2014
STATUS
approved