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A063685 Numbers k such that !k + phi(k) - 1 is prime. 0
2, 3, 4, 5, 11, 20, 85, 212, 4925 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
a(10) > 5000. - J.W.L. (Jan) Eerland, Nov 19 2022
a(10) > 13469. - J.W.L. (Jan) Eerland, Nov 20 2022
LINKS
MATHEMATICA
n=1; Monitor[Parallelize[While[True, If[PrimeQ[Sum[Factorial[k], {k, 0, n-1}]+EulerPhi[n]-1], Print[n]]; n++]; n], n] (* J.W.L. (Jan) Eerland, Nov 19 2022 *)
PROG
(PARI) f(n) = sum(k=0, n-1, k!); \\ A003422
for(n=1, 10^6, if(isprime(f(n)+eulerphi(n)-1), print(n)))
CROSSREFS
Cf. A003422.
Sequence in context: A118968 A073528 A116067 * A006481 A118597 A083160
KEYWORD
nonn,more
AUTHOR
Jason Earls, Aug 22 2001
EXTENSIONS
a(9) from J.W.L. (Jan) Eerland, Nov 19 2022
STATUS
approved

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Last modified February 22 18:56 EST 2024. Contains 370260 sequences. (Running on oeis4.)