A001369 Blocks of increasing length using 1,2,3,...,9,10; omit leading 0's.

1, 23, 456, 7891, 1234, 567891, 123456, 78910123, 456789101, 2345678910, 12345678910, 123456789101, 2345678910123, 45678910123456, 789101234567891, 123456789101234, 56789101234567891, 12345678910123456, 7891012345678910123, 45678910123456789101

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• base

Comments

It appears that the first digit repeats 1, 2, 4, 7, 1, 5, 1, 7, 4, 2, 1. - T. D. Noe, Apr 05 2011

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..200

Crossrefs

Cf. A066547, A007923.

Programs

Mathematica

nn = 20; d = Flatten[Table[{1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 0}, {Ceiling[nn (nn + 1)/22]}]]; Table[e = (n + 1) n/2; s = e - n + 1; FromDigits[d[[s ;; e]]], {n, nn}] (* T. D. Noe, Apr 05 2011 *)

PARI

N=[]; k=Mod(-1,10); for(n=1, 20, while(#NM. F. Hasler, May 08 2014