1,1

All k<10^8 have been checked. All of these numbers are multiples of 3.

Table of n, a(n) for n=1..51.

Cf. A066426 (least k such that phi(n)+phi(k)=phi(n+k)).

Sequence in context: A243128 A306771 A216521 * A261274 A014493 A147025

Adjacent sequences: A110169 A110170 A110171 * A110173 A110174 A110175

nonn

T. D. Noe, Jul 15 2005

approved