a(1) = 0, a(2) = 0; for n > 2, a(n) - a(n-3) - a(n-5) - ... - a(n-p) = n if n is prime, otherwise = 0, where p = largest prime < n.

A002123

a(1) = 0, a(2) = 0; for n > 2, a(n) - a(n-3) - a(n-5) - ... - a(n-p) = n if n is prime, otherwise = 0, where p = largest prime < n.

Terms

    a(0) =0a(1) =0a(2) =3a(3) =0a(4) =5a(5) =-3a(6) =7a(7) =-8a(8) =3a(9) =-15a(10) =22a(11) =-15a(12) =39a(13) =-35a(14) =38a(15) =-72a(16) =85a(17) =-111a(18) =152a(19) =-175a(20) =241a(21) =-308a(22) =414a(23) =-551a(24) =655a(25) =-897a(26) =1164a(27) =-1463a(28) =2001a(29) =-2538

External references