A343829 Distinct values of gcd(B(2*j), B(2*j+2)) in the order of their appearance, where B(k) = A027641(k).

1, 587, 491, 37, 103, 59, 131, 67, 283, 101, 691, 157, 617, 593, 149, 233, 683, 271, 263, 307, 577, 653, 379, 257, 467, 293, 21719, 541, 1721, 631, 3617, 409, 839, 463

Offset: 1

Author

Robert G. Wilson v, Apr 30 2021

Keywords

• nonn
• more

Comments

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

Crossrefs

Cf. A000928, A027641, A343745.

Programs

Mathematica

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