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A234695 Primes p with prime(p) - p + 1 also prime. 38
2, 3, 5, 7, 13, 17, 23, 31, 41, 43, 61, 71, 83, 89, 103, 109, 139, 151, 173, 181, 199, 211, 223, 241, 271, 277, 281, 293, 307, 311, 317, 337, 349, 353, 367, 463, 499, 541, 563, 571, 601, 661, 673, 709, 719, 743, 751, 757, 811, 823, 827, 883, 907, 911, 953 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
By the conjecture in A234694, this sequence should have infinitely many terms.
LINKS
Z.-W. Sun, Problems on combinatorial properties of primes, arXiv:1402.6641, 2014
FORMULA
a(n) = prime(A234852(n)). - M. F. Hasler, Dec 31 2013
EXAMPLE
a(1) = 2 since prime(2) - 1 = 2 is prime.
a(2) = 3 since prime(3) - 2 = 3 is prime.
a(3) = 5 since prime(5) - 4 = 7 is prime.
a(4) = 7 since prime(7) - 6 = 11 is prime.
MATHEMATICA
n=0; Do[If[PrimeQ[Prime[Prime[k]]-Prime[k]+1], n=n+1; Print[n, " ", Prime[k]]], {k, 1, 1000}]
PROG
(PARI) forprime(p=1, 999, isprime(prime(p)-p+1)&&print1(p", ")) \\ - M. F. Hasler, Dec 31 2013
CROSSREFS
Sequence in context: A089438 A155777 A262839 * A067905 A042993 A308711
KEYWORD
nonn
AUTHOR
Zhi-Wei Sun, Dec 29 2013
STATUS
approved

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Last modified March 28 10:55 EDT 2024. Contains 371241 sequences. (Running on oeis4.)