1,2

for n=1 sum{p-1|p is prime and divisor of 1} is zero.

Table of n, a(n) for n=1..75.

a(n)=A055631(n)+A173557(n).

Cf. A055631, A173557.

Sequence in context: A095728 A279354 A278220 * A163897 A278541 A278257

Adjacent sequences: A174144 A174145 A174146 * A174148 A174149 A174150

nonn

Juri-Stepan Gerasimov, Mar 09 2010

Formula index corrected, a 62 replaced by 64 - R. J. Mathar, Apr 25 2010.

approved