A082129 Rounded base-2 logarithm of A082128(n).

4, 2, 2, 4, 3, 1, 5, 4, 6, 9, 17, 22, 33, 53, 76, 114, 171, 260, 390, 585, 874, 1311, 1970, 2955, 4429, 6647, 9967, 14954, 22431, 33643, 50468, 75702, 113553, 170326, 255489, 383237

Offset

1,1

Links

Table of n, a(n) for n=1..36.

Prog

(PARI) p=21*4*5*13; for(n=1, 50, v=divisors(p); r=sqrt(p); t=0; for(k=1, matsize(v)[2], if(v[k]>=r, t=k; break)); if(v[t]^2==p, u=t, u=t-1); if(v[t]-v[u]<2, u=u-1; t=t+1); print1(round(log(v[t]-v[u])/log(2))", "); p=p*(v[t]-v[u]))

Crossrefs

Cf. A082127, A082128.

Sequence in context: A251628 A170988 A141035 * A100854 A194688 A317389

Adjacent sequences: A082126 A082127 A082128 * A082130 A082131 A082132

Keyword

nonn,hard,more

Author

Ralf Stephan, Apr 04 2003

Extensions

Revised and more terms from Sean A. Irvine, Nov 25 2025

Status

approved