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

1,2

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

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 *)

Prog

(PARI) N=[]; k=Mod(-1, 10); for(n=1, 20, while(#N<n, N=concat(N, Vec(Str(1+lift(k++))))); print1(eval(concat(vecextract(N, 2^n-1)))", "); N=vecextract(N, Str("^.."n))) \\ M. F. Hasler, May 08 2014

Crossrefs

Cf. A066547, A007923.

Sequence in context: A076068 A062273 A066547 * A007923 A080479 A053067

Adjacent sequences: A001366 A001367 A001368 * A001370 A001371 A001372

Keyword

nonn,base

Author

N. J. A. Sloane

Status

approved