1,4
Cf. A005142, A024607
Sequence in context: A001572 A131342 A005142 * A106063 A006483 A177960
Adjacent sequences: A165449 A165450 A165451 * A165453 A165454 A165455
nonn
Friedrich Regen (friedrich.regen(AT)tu-ilmenau.de), Sep 20 2009