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 A344963 Numbers k such that (2*k+1)*k!+1 is prime. 1
 0, 2, 3, 5, 11, 18, 68, 77, 124, 173, 205, 293, 1037, 1530, 1905, 2342, 3401, 4372, 4679, 5385 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(21) > 10^4. LINKS MAPLE select(k -> isprime((2*k+1)*k!+1), [\$0 .. 300])[]; MATHEMATICA Do[If[PrimeQ[(2*k + 1)*Factorial[k] + 1], Print[k]], {k, 0, 3000}] PROG (PARI) for(k=0, 3000, if(isprime((2*k+1)*k!+1), print1(k", "))) (SageMath) for k in range(3000):     if is_prime((2*k+1)*factorial(k) + 1):         print(k) CROSSREFS Cf. A002981, A344991. Sequence in context: A057652 A025067 A024371 * A231479 A084758 A087582 Adjacent sequences:  A344960 A344961 A344962 * A344964 A344965 A344966 KEYWORD nonn,hard,more AUTHOR Reza K Ghazi, Jun 07 2021 STATUS approved

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Last modified August 7 20:35 EDT 2022. Contains 355994 sequences. (Running on oeis4.)