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A234387 a(n) = n-th smallest prime congruent to 1 modulo prime(n). 1
3, 13, 41, 113, 331, 443, 613, 1103, 1013, 1741, 2543, 3257, 3691, 4129, 4889, 6997, 6491, 8053, 8443, 12071, 11681, 12799, 15439, 18869, 20759, 21211, 20807, 27179, 33791, 28703, 37339, 39301, 37813, 53377, 51853, 54059, 62801, 60637, 74149, 72661, 77687, 62989, 81749, 79903, 79589, 109849, 102547 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Zak Seidov and Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 (first 1000 terms from Seidov)

EXAMPLE

a(3) = 41 because prime(3) = 5 and primes == 1 mod 5 are 11, 31, 41;

a(4) = 113 because prime(4) = 7 and primes == 1 mod 7 are 29, 43, 71, 113.

MATHEMATICA

Reap[Sow[3]; Do[c=0; q=Prime[n]; p=1; While[c<n, p=p+2q; If[PrimeQ[p], c++]]; Sow[p], {n, 2, 100}]][[2, 1]]

PROG

(PARI) a(n)=if(n<2, return(3)); my(p=prime(n), q=2*p+1); while(n, if(isprime(q), n--); q+= 2*p); q-2*p \\ Charles R Greathouse IV, Dec 26 2013

CROSSREFS

Cf. A035095, A234372.

Sequence in context: A309139 A049167 A241527 * A173867 A121162 A146018

Adjacent sequences: A234384 A234385 A234386 * A234388 A234389 A234390

KEYWORD

nonn

AUTHOR

Zak Seidov, Dec 25 2013

STATUS

approved

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Last modified February 3 15:25 EST 2023. Contains 360035 sequences. (Running on oeis4.)