A375345 a(n) = b(n, n-1) where b(n, m) = b(n, m-1) + gcd(b(n, m-1), n-m) for m > 0 with b(n, 0) = n.

3, 5, 7, 11, 11, 13, 17, 17, 19, 23, 23, 29, 29, 29, 31, 41, 53, 37, 41, 41, 43, 47, 47, 59, 53, 53, 59, 59, 59, 61, 89, 71, 67, 71, 71, 73, 83, 83, 79, 83, 83, 89, 89, 89, 97, 101, 109, 97, 101, 101, 103, 107, 107, 109, 113, 113, 139, 131, 131, 131, 131, 131

Offset

2,1

Comments

It is conjectured that all terms are prime.

Conjecture was checked up to 10^6. - Vaclav Kotesovec, Sep 10 2024

Links

Table of n, a(n) for n=2..63.

Prog

(PARI) a(n) = my(A = n); for(i=1, n-1, A += gcd(A, n-i)); A

Crossrefs

Sequence in context: A241957 A112070 A208643 * A123252 A352185 A066168

Adjacent sequences: A375340 A375341 A375342 * A375347 A375349 A375350

Keyword

nonn,easy,new

Author

Mikhail Kurkov, Aug 12 2024

Status

approved