1,1

Number n belongs to this sequence if both n and n-1 belong to A020757.

Table of n, a(n) for n=1..53.

A020757

Sequence in context: A043929 A180656 A034070 * A045241 A046041 A140151

Adjacent sequences: A168308 A168309 A168310 * A168312 A168313 A168314

nonn

Tanya Khovanova, Nov 22 2009

approved