A137655 Working in base 3, a(n+1) = number of preceding terms that are contained in a(n); a(0)=0.

0, 1, 1, 2, 1, 3, 5, 5, 6, 3, 6, 4, 4, 5, 7, 5, 8, 2, 2, 3, 7, 8, 5, 11, 11, 12, 10, 8, 6, 7, 9, 8, 7, 10, 9, 9, 10, 10, 11, 13, 6, 8, 8, 9, 11, 14, 14, 15, 17, 18, 9, 12, 11, 15, 18, 10, 12, 12, 13, 7, 11, 16, 17, 19, 12, 14, 16, 18, 11, 17, 20, 9, 13, 8, 10, 13, 9, 14, 17, 22, 14, 18, 12, 15

Offset

0,4

Comments

a(A137656(n)) = n and a(m) <> n for m < A137656(n).

Links

R. Zumkeller, Table of n, a(n) for n = 0..25000

Eric Weisstein's World of Mathematics, Ternary

Example

a(15)=#{a(1),a(2),a(3),a(4),a(14)}=5;
a(16)=#{a(1),a(2),a(3),a(4),a(6),a(7),a(13),a(15)}=8;
a(17)=#{a(3),a(16)}=2.

Crossrefs

Cf. A007089, A131813.

Sequence in context: A184250 A330411 A306977 * A355621 A296064 A167595

Adjacent sequences: A137652 A137653 A137654 * A137656 A137657 A137658

Keyword

nonn,base,hear,look

Author

Reinhard Zumkeller, Feb 01 2008

Status

approved