1,1

All terms are of the form 2p, p prime.

The prime (2^4414 + 3^4414)/13 = 79300327387 ...611266 985181 has 2105 decimal digits.

Table of n, a(n) for n=1..12.

10 is in the sequence because (2^10+ 3^10)/13 = 60073/13 = 4621 is prime.

with(numtheory):for n from 1 to 4500 do: x:= (2^n + 3^n)/13:if floor(x)=x and

type(x, prime)=true then printf(`%d, `, n):else fi:od:

Cf. A057469

Sequence in context: A207574 A278972 A241817 * A023387 A119623 A129119

Adjacent sequences: A181625 A181626 A181627 * A181629 A181630 A181631

nonn

Michel Lagneau, Nov 18 2010

a(12) from D. S. McNeil, Nov 18 2010

approved