login
A237344
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(7).
2
0, 1, 2, 3, 4, 5, 6, 7, 49, 50, 51, 52, 53, 54, 55, 56, 57, 549, 550, 551, 552, 553, 554, 555, 556, 557, 5549, 5550, 5551, 5552, 5553, 5554, 5555, 5556, 5557, 55549, 55550, 55551, 55552, 55553, 55554, 55555, 55556, 55557, 555549, 555550, 555551, 555552
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 -10*x^15 +10*x^13 +20*x^12 +30*x^11 +40*x^10 +50*x^9 +49*x^8 +7*x^7 +6*x^6 +5*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
MATHEMATICA
CoefficientList[Series[(10 x^17 - 20 x^16 - 10 x^15 + 10 x^13 + 20 x^12 + 30 x^11 + 40 x^10 + 50 x^9 + 49 x^8 + 7 x^7 + 6 x^6 + 5 x^5 + 4 x^4 + 3 x^3 + 2 x^2 + x)/(10 x^18 -11 x^9 + 1), {x, 0, 50}], x] (* Vincenzo Librandi, Sep 24 2014 *)
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Vincenzo Librandi, Feb 06 2014
EXTENSIONS
Definition by N. J. A. Sloane, Feb 07 2014
STATUS
approved