A096171 Numbers n such that n^4+1 is an odd semiprime.

8, 10, 12, 14, 18, 22, 26, 30, 32, 36, 38, 40, 42, 50, 52, 58, 62, 68, 72, 78, 84, 86, 92, 94, 98, 100, 102, 108, 112, 114, 116, 120, 122, 124, 128, 130, 138, 146, 148, 152, 158, 162, 166, 170, 172, 176, 184, 186, 200, 212, 214, 216, 218, 222, 224, 226, 234, 250, 252

Offset

1,1

Links

Hugo Pfoertner, Table of n, a(n) for n = 1..10000

Example

a(1)=8 because 8^4 + 1 = 4097 = 17*241;
a(2)=10: 10^4 + 1 = 10001 = 73*137.

Mathematica

Select[Range[2, 300, 2], PrimeOmega[#^4+1]==2&] (* Harvey P. Dale, Dec 25 2021 *)

Prog

(PARI) isA096171(n) = {local(m); m=n^4+1; (m%2==1)&&(bigomega(m)==2)} \\ Michael B. Porter, Feb 02 2010

Crossrefs

Cf. A000068 (n^4+1 is prime), A037896 (primes of the form n^4+1), A096169 ((n^4+1)/2 is prime), A069170 (primes of the form (n^4+1)/2), A096172 (largest prime factor of n^4+1), A046388.

Sequence in context: A356657 A008557 A161425 * A337252 A154786 A335013

Adjacent sequences: A096168 A096169 A096170 * A096172 A096173 A096174

Keyword

nonn

Author

Hugo Pfoertner, Jun 19 2004

Status

approved