a(n) = 1+2*(d1 + 1)*(d2 + 1)*...*(dk + 1), where d1, d2, ..., dk are the prime factors of the n-th Fermat pseudoprime to base 2 A001567(n).
A216646
a(n) = 1+2*(d1 + 1)*(d2 + 1)*...*(dk + 1), where d1, d2, ..., dk are the prime factors of the n-th Fermat pseudoprime to base 2 A001567(n).
Terms
- a(0) =769a(1) =1729a(2) =2113a(3) =3025a(4) =2961a(5) =4481a(6) =6145a(7) =4321a(8) =6481a(9) =5625a(10) =7169a(11) =6841a(12) =8361a(13) =9289a(14) =12289a(15) =9729a(16) =11265a(17) =16129a(18) =16281a(19) =17065a(20) =24769a(21) =21761a(22) =21249a(23) =26641a(24) =34561a(25) =36289a(26) =34049a(27) =28081a(28) =32257a(29) =29745
External references
- oeis: A216646