1,6

Table of n, a(n) for n=1..20.

Below 32 the only odd split number is 21, so a(5) = 1. (In this range there are also 11 primes, 7 true prime powers, 1 composite connected number (15) and 4 even split numbers.)

Cf. A029837, A036378-A036390.

Sequence in context: A097809 A272144 A036389 * A037166 A118892 A100691

Adjacent sequences: A036385 A036386 A036387 * A036389 A036390 A036391

nonn

Labos Elemer

approved