A152598 Records in A001917.

1, 2, 6, 8, 18, 24, 31, 38, 72, 105, 129, 630, 1285, 1542, 2048, 3112, 3512, 7710, 7760, 9728, 27594, 48834, 60787, 104694, 140896, 282224, 384800, 683720, 1205998, 1240672, 1407592, 4012472, 4429250, 4628480, 16657248, 69273666, 107700228, 254290896, 319233186

Offset: 1

Author

Klaus Brockhaus, Dec 09 2008

Keywords

• nonn

Examples

			First few terms of A001917 are 1, 1, 2, 1, 1, 2, 1, 2, 1, 6, so a(1) to a(3) are 1, 2, 6.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..47

Crossrefs

Cf. A001917 ((p-1)/x, where p = prime(n) and x = smallest positive integer such that 2^x == 1 mod p), A152597 (where records occur in A001917).

Programs

Magma

R:=[]; r:=0; for n in [2..100000] do p:=NthPrime(n); a:=(p-1)/Modorder(2, p); if r lt a then r:=a; Append(~R,a); end if; end for; print R;

Mathematica

ord[n_]:=Module[{x=1},While[PowerMod[2,x,n]!=1,x++];(n-1)/x];DeleteDuplicates[ ord/@Prime[Range[2,10^5]],GreaterEqual] (* The program generates the first 21 terms of the sequence. *) (* Harvey P. Dale, Oct 09 2022 *)

Formula

a(n) = A001917(A152597(n)). - Amiram Eldar, Nov 16 2023

Extensions

More terms from Vassilis Papadimitriou, Mar 06 2010

More terms from Vassilis Papadimitriou, Mar 19 2010

a(37) from Amiram Eldar, Mar 08 2019

a(38)-a(39) from Amiram Eldar, Nov 16 2023