A122462 a(n) = gcd(b(n-1),b(n)), where b(i) = A122280(i).

2, 2, 3, 3, 3, 2, 5, 5, 3, 2, 2, 7, 7, 3, 2, 11, 11, 3, 3, 2, 2, 13, 13, 3, 2, 17, 17, 3, 2, 5, 5, 7, 2, 19, 19, 3, 5, 2, 23, 23, 3, 2, 2, 2, 2, 11, 5, 2, 29, 29, 3, 7, 7, 2, 31, 31, 3, 2, 13, 5, 2, 2, 37, 37, 3, 3, 3, 2, 2, 41, 41, 3, 3, 7, 11, 2, 43, 43, 3, 2, 2, 47, 47, 3, 2, 2, 5, 5, 5, 2, 2, 2

Offset

3,1

Comments

Primes arising in A122280 as greatest common divisor.

Links

Table of n, a(n) for n=3..94.

Prog

(PARI) {m=100; z=2*m; w=vectorsmall(z); b=1; a=2; w[b]=1; w[a]=1; stop=0; n=3; while(!stop&&n<=m, j=1; while(j<=z&&(w[j]==1||!isprime(p=gcd(a, j))), j++); if(j>z, stop=1, print1(p, ", "); a=j; w[a]=1; n++))}

Crossrefs

Cf. A122280.

Sequence in context: A106482 A301805 A260236 * A215406 A231717 A253315

Adjacent sequences: A122459 A122460 A122461 * A122463 A122464 A122465

Keyword

nonn

Author

Klaus Brockhaus, Sep 09 2006

Status

approved