1,2

a(3) = 125 = 5^3 = 31*a(2) + 1 where a(2) = 4=2^2 = 3*1 + 1.

(PARI) v=vector(15):v[2]=4:print1("1, 4, "):for(n=3, 15, for(k=2, 10^8, if(((k^n)%(v[n-1]))==1, print1(k^n", "):v[n]=k^n:break)))

Adjacent sequences: A068891 A068892 A068893 this_sequence A068895 A068896 A068897

Sequence in context: A090082 A068891 A073351 this_sequence A116944 A124260 A054053

nonn

Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Mar 20 2002

Corrected and extended by Ralf Stephan (ralf(AT)ark.in-berlin.de), Mar 21 2003