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 A318751 Prime-indexed primes q such that prime(q)-q-1 is a prime indexed prime. 2
 5, 17, 353, 859, 4787, 5441, 6353, 6841, 7883, 12503, 13037, 16061, 18617, 20959, 25357, 29137, 33029, 38351, 39199, 44729, 46237, 69491, 80429, 82217, 85597, 89989, 92779, 97001, 107903, 129287, 132611, 139661, 170707, 172721, 187123, 230453, 238943, 242129, 257689, 259151, 292841, 312773, 328789, 341423, 346147 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS This sequence and the sequence of resulting primes, prime(q)-q-1 (5, 41, 2027, 5801, 41491, ...), are subsequences of A006450, the prime-indexed primes. LINKS Harvey P. Dale, Table of n, a(n) for n = 1..500 N. Fernandez, An order of primeness, F(p) N. Fernandez, An order of primeness [cached copy, included with permission of the author] MAPLE N := 1000000; for n to N do if isprime(n) then q := ithprime(n); Z := numtheory[pi](n); S := q-n-1; W := numtheory[pi](S); if isprime(Z) and isprime(S) and isprime(W) then print(n); end if: end if: end do: MATHEMATICA pipQ[n_]:=Module[{c=Prime[n]-n-1}, AllTrue[{PrimePi[n], c, PrimePi[ c]}, PrimeQ]]; Select[Prime[Range[30000]], pipQ] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 30 2020 *) PROG (PARI) isok(p) = isprime(p) && isprime(primepi(p)) && isprime(q=prime(p)-p-1) && isprime(primepi(q)); \\ Michel Marcus, Sep 03 2018 CROSSREFS Cf. A000040, A006450, A318292, A318752. Sequence in context: A286678 A081479 A335313 * A096996 A256236 A070294 Adjacent sequences: A318748 A318749 A318750 * A318752 A318753 A318754 KEYWORD nonn AUTHOR David James Sycamore, Sep 02 2018 EXTENSIONS Corrected and extended by Harvey P. Dale, Jun 30 2020 STATUS approved

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Last modified May 22 15:18 EDT 2024. Contains 372758 sequences. (Running on oeis4.)