A004073 Start with a(1)=1; to get a(n) replace each i in a(n-1) with 12...i, then append n.

1, 12, 1123, 11121234, 1111211212312345, 11111211121121231121231234123456, 1111112111121112112123111211212311212312341121231234123451234567

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• base

Comments

Digits sum to A000225.

Links

• T. Kubo and R. Vakil, On Conway's recursive sequence, Discr. Math. 152 (1996), 225-252.

Extensions

The next term is too large to include.