A123179 a(1)=1 a(2)=121 and a(n)=a(n-1) n 2 n 3 n ... n (n-1) n 1, using concatenation.

1, 121, 1213231, 1213231424341, 121323142434152535451, 1213231424341525354516263646561, 1213231424341525354516263646561727374757671

Offset

1,2

Comments

An example of transition complete sequences, when n <= 9. One needs to consider the base 10 complications when n >= 10. The number of digits is given by d(n)=d(n-1)+2n-2 which is A002061.

Links

Table of n, a(n) for n=1..7.

Example

a(4)=1213231424341=1213231 + 4 2 4 3 4 1.

Crossrefs

Cf. A108713, A002061.

Sequence in context: A136094 A317197 A082215 * A245593 A053885 A068490

Adjacent sequences: A123176 A123177 A123178 * A123180 A123181 A123182

Keyword

nonn,base

Author

Douglas Stones (dssto1(AT)student.monash.edu.au), Oct 03 2006

Status

approved