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A084830 Numbers n such that (n!)^2 + n! - 1 is prime. 0
2, 3, 4, 5, 6, 14, 17, 50, 111, 254, 506 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

H. Dubner, Factorial and primorial primes, J. Rec. Math., 19 (No. 3, 1987).

LINKS

Table of n, a(n) for n=1..11.

Dorin Andrica, George C. Ţurkaş, An elliptic Diophantine equation from the study of partitions, Stud. Univ. Babeş-Bolyai Math. (2019) Vol. 64, No. 3, 349-356.

EXAMPLE

5 is in the sequence because (5!)^2+5!-1=14519 is prime.

MATHEMATICA

Do[If[PrimeQ[n!^2+n!-1], Print[n]], {n, 600}]

CROSSREFS

Cf. A002981, A002982.

Sequence in context: A039016 A249102 A250047 * A116044 A116027 A085157

Adjacent sequences:  A084827 A084828 A084829 * A084831 A084832 A084833

KEYWORD

more,nonn

AUTHOR

Farideh Firoozbakht, Jul 12 2003

STATUS

approved

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Last modified May 26 04:43 EDT 2022. Contains 354074 sequences. (Running on oeis4.)