A250199 Smallest pseudoprime (>prime(n)) to base prime(n).

341, 91, 124, 25, 15, 21, 45, 45, 33, 35, 49, 45, 105, 77, 65, 65, 87, 91, 85, 105, 111, 91, 105, 99, 105, 175, 133, 133, 117, 133, 153, 143, 148, 161, 175, 175, 186, 186, 231, 205, 185, 195, 217, 276, 231, 225, 217, 231, 285, 285, 259, 255, 363, 289, 301, 341, 286, 341, 322, 329

Offset

1,1

Comments

Subsequence of A007535, see formula.

Links

Eric Chen, Table of n, a(n) for n = 1..4096

Formula

a(n) = A007535(A000040(n)).

Example

a(7) = 45 because the 7th prime is 17, and the smallest pseudoprime (> 17) to base 17 is 45.

Mathematica

f[n_] := Block[{b = Prime[n], k = Prime[n] + 1}, While[PrimeQ[k] || PowerMod[b, k - 1, k] != 1, k++]; k]; Array[f, 60]

Prog

a(n) = for(k=prime(n)+1, 2^24, if(Mod(prime(n), k)^(k-1)==Mod(1, k) && !isprime(k), return(k)))

Crossrefs

Cf. A007535, A090086, A108162, A098650.

Sequence in context: A057598 A271801 A322120 * A271874 A025335 A025327

Adjacent sequences: A250196 A250197 A250198 * A250200 A250201 A250202

Keyword

nonn

Author

Eric Chen, Feb 21 2015

Status

approved