login
Distinct values of gcd(B(2*j), B(2*j+2)) in the order of their appearance, where B(k) = A027641(k).
0

%I #13 Jun 01 2021 10:51:28

%S 1,587,491,37,103,59,131,67,283,101,691,157,617,593,149,233,683,271,

%T 263,307,577,653,379,257,467,293,21719,541,1721,631,3617,409,839,463

%N Distinct values of gcd(B(2*j), B(2*j+2)) in the order of their appearance, where B(k) = A027641(k).

%C Conjecture: all terms greater than 1 are irregular primes (A000928) or a product of irregular primes.

%t a = Numerator@ BernoulliB@ 2; b = Numerator@ BernoulliB@ 4; k = 6; lst = {}; While[k < 75001, a = b; b = Numerator@ BernoulliB@ k; g = GCD[a, b]; If[ !MemberQ[ lst, g], AppendTo[lst, g]]; k += 2]; lst

%Y Cf. A000928, A027641, A343745.

%K nonn,more

%O 1,2

%A _Robert G. Wilson v_, Apr 30 2021