a(n) is the least number of the form p^2 + q^2 - 2 for primes p and q that is an odd multiple of 2^n, or -1 if there is no such number.

A359439

a(n) is the least number of the form p^2 + q^2 - 2 for primes p and q that is an odd multiple of 2^n, or -1 if there is no such number.

Terms

    a(0) =11a(1) =6a(2) =-1a(3) =56a(4) =16a(5) =32a(6) =192a(7) =128a(8) =2816a(9) =1536a(10) =15360a(11) =30720a(12) =12288a(13) =73728a(14) =147456a(15) =32768a(16) =196608a(17) =1179648a(18) =22806528a(19) =11010048a(20) =34603008a(21) =31457280a(22) =314572800a(23) =679477248a(24) =50331648a(25) =301989888a(26) =1006632960a(27) =10871635968a(28) =20132659200a(29) =4831838208

External references