OFFSET
1,1
COMMENTS
Numbers with at least 2 digits, ending in digits d and d+1 (and d<=8). - Joerg Arndt, Aug 28 2013
First differences are 9-periodic: 11,11,11,11,11,11,11,11,12. - Ralf Stephan, Aug 28 2013
LINKS
JungHwan Min, Table of n, a(n) for n = 1..1000
FORMULA
From Chai Wah Wu, Dec 23 2016: (Start)
a(n) = a(n-1) + a(n-9) - a(n-10) for n > 10.
G.f.: x*(-x^9 + 12*x^8 + 11*x^7 + 11*x^6 + 11*x^5 + 11*x^4 + 11*x^3 + 11*x^2 + 11*x + 12)/(x^10 - x^9 - x + 1). (End)
MATHEMATICA
Reap[Do[If[Sort@IntegerDigits[n] == Sort@IntegerDigits[n + 9], Sow[n]], {n, 500}]][[-1, 1]] (* JungHwan Min, Jan 05 2016 *)
Select[Range[0, 1000], Sort[IntegerDigits[#]] == Sort[IntegerDigits[# + 9]] &] (* Vincenzo Librandi, Jan 06 2016 *)
PROG
(Magma) [n: n in [0..600] | Sort(Intseq(n)) eq Sort(Intseq(n+9))]; // Bruno Berselli, Jan 08 2016
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Alan Bryant, Aug 16 2013
STATUS
approved