A242645 a(n) = concatenation of decimal expansions of powers of 11 (in decreasing order).

1, 111, 121111, 1331121111, 146411331121111, 161051146411331121111, 1771561161051146411331121111, 194871711771561161051146411331121111, 214358881194871711771561161051146411331121111, 2357947691214358881194871711771561161051146411331121111

Offset

0,2

Comments

A068704(11) (presently unknown) is either 0, if every term here is composite, or the index of the first prime in the sequence.

Links

Alois P. Heinz, Table of n, a(n) for n = 0..42

Formula

a(n) is the concatenation of 11^n, 11^(n-1), ..., 121, 11, 1.

Maple

a:= proc(n) option remember;
      `if`(n=0, 1, parse(cat(11^n, a(n-1))))
    end:
seq(a(n), n=0..10);  # Alois P. Heinz, May 24 2014

Crossrefs

Cf. A068704, A242646.

Sequence in context: A152775 A362118 A242646 * A262647 A262631 A259747

Adjacent sequences: A242642 A242643 A242644 * A242646 A242647 A242648

Keyword

nonn,base

Author

N. J. A. Sloane, May 23 2014

Status

approved