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A096171 Numbers n such that n^4+1 is an odd semiprime. 5
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 (list; graph; refs; listen; history; text; internal format)
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: A020744 A008557 A161425 * A337252 A154786 A335013

Adjacent sequences:  A096168 A096169 A096170 * A096172 A096173 A096174

KEYWORD

nonn

AUTHOR

Hugo Pfoertner, Jun 19 2004

STATUS

approved

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Last modified August 10 00:32 EDT 2022. Contains 356026 sequences. (Running on oeis4.)