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A361696 Semiprimes of the form k^2 + 5. 0

%I #11 May 13 2023 18:32:18

%S 6,9,14,21,69,86,201,329,446,489,581,681,734,789,905,1094,1769,1941,

%T 2606,2921,3254,3369,3849,3974,4101,4629,4766,6729,7061,7401,8105,

%U 8654,9609,9806,10409,10821,11669,12326,13929,17429,17961,19049,20741,23109,23721,24341,27561,30281,31334,32405

%N Semiprimes of the form k^2 + 5.

%F a(n) = A242333(n)^2 + 5.

%e 69 is a term because 8^2 + 5 = 69 = 3*23.

%o (PARI) isok(k) = issquare(k-5) && (bigomega(k)==2); \\ _Michel Marcus_, Mar 27 2023

%Y Cf. A144255, A242333, A360739, A360740, A360741.

%Y Intersection of A117951 and A001358.

%K nonn,easy

%O 1,1

%A _Elmo R. Oliveira_, Mar 20 2023

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Last modified September 5 08:10 EDT 2024. Contains 375696 sequences. (Running on oeis4.)