A090085 Smallest odd pseudoprimes to base n exceeding n (like A007535 but with smallest odd terms instead of few even ones).

9, 341, 91, 15, 217, 35, 25, 9, 91, 33, 15, 65, 21, 15, 341, 51, 45, 25, 45, 21, 55, 69, 33, 25, 39, 27, 65, 45, 35, 49, 49, 33, 85, 35, 51, 91, 45, 39, 95, 91, 105, 205, 77, 45, 133, 133, 65, 49, 75, 51, 65, 85, 65, 55, 63, 57, 65, 133, 87, 341, 91, 63, 341, 65, 133, 91, 85

Offset: 1

Author

Labos Elemer, Nov 25 2003

Keywords

• nonn

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
• Index entries for sequences related to pseudoprimes

Crossrefs

Cf. A007535.

Programs

Mathematica

ds[x_, b_] := Mod[ -1+b^(x-1), x] a[n_] := Block[{m=1, s=ds[m, n]}, While[(s !=0||PrimeQ[m])||Equal[m, 1] ||!Greater[m, n]||EvenQ[m], m++ ];m]; t=Table[a[n], {n, 1, 256}]

PARI

a(n)=my(k=n+if(n%2,2,1));while(Mod(n,k)^(k-1)!=1 || isprime(k), k+=2);k \\ Charles R Greathouse IV, Apr 12 2012