3,3

a(n)=A007917(n)*A007918(n)-A007917(n-1)*A007918(n+1) =A030664(n)-A013638(n) =A056140(n)-A056139(n)

a(n)=A056140(n) if n is prime, a(n)=0 otherwise

a(3)=3*3-2*5=-1, a(4)=3*5-3*5=0

Cf. A056139, A056140.

Sequence in context: A108174 A134530 A126813 this_sequence A125961 A016681 A076290

Adjacent sequences: A056138 A056139 A056140 this_sequence A056142 A056143 A056144

easy,sign

Henry Bottomley (se16(AT)btinternet.com), Jun 15 2000