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A237995 Primes p such that  p^4 - p^3 - 1 is also prime. 1
2, 3, 5, 11, 17, 53, 59, 101, 103, 151, 157, 167, 193, 197, 239, 353, 379, 397, 419, 433, 467, 479, 503, 599, 641, 659, 661, 743, 787, 881, 907, 911, 983, 1049, 1109, 1123, 1153, 1201, 1229, 1291, 1307, 1373, 1399, 1429, 1531, 1601, 1621, 1663, 1747, 1753 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

K. D. Bajpai, Table of n, a(n) for n = 1..3700

EXAMPLE

5 is in the sequence because 5 is prime and 5^4 - 5^3 - 1 = 499 is also prime.

17 is in the sequence because 17 is prime and 17^4 - 17^3 - 1 = 78607 is also prime.

MAPLE

KD := proc() local a, b; a:= ithprime(n); b:= a^4-a^3-1; if isprime(b) then RETURN (a); fi; end: seq(KD(), n=1..400);

MATHEMATICA

c = 0; a = 2; Do[k = Prime[n]; If[PrimeQ[k^4 - k^3 - 1], c = c + 1;  Print[c, " ", k]], {n, 100000}]; (* Bajpai *)

Select[Prime[Range[200]], PrimeQ[#^4 - #^3 - 1] &] (* Alonso del Arte, Feb 17 2014 *)

PROG

(PARI) s=[]; forprime(p=2, 2000, if(isprime(p^4-p^3-1), s=concat(s, p))); s \\ Colin Barker, Feb 17 2014

CROSSREFS

Cf. A000040, A237639, A237641, A237642.

Sequence in context: A007755 A060611 A077497 * A178606 A097048 A286268

Adjacent sequences:  A237992 A237993 A237994 * A237996 A237997 A237998

KEYWORD

nonn

AUTHOR

K. D. Bajpai, Feb 16 2014

STATUS

approved

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Last modified October 18 17:13 EDT 2019. Contains 328186 sequences. (Running on oeis4.)