A082121 Smallest difference > 1 between d and p/d for any divisor d of the partial product p of the sequence, starting with 7.

7, 6, 11, 19, 37, 109, 515, 3301, 267271, 130914197, 209015618081, 887384060899271, 58605404461258015758293, 2968102112607912669687621496462081, 14260730459101877586974713921688751629030028412259, 22832002460095313751743325558970299368361276033413155981955022423880088921

Offset

1,1

Links

Table of n, a(n) for n=1..16.

Prog

(PARI) p=7; print1(p, ", "); 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(v[t]-v[u]", "); p=p*(v[t]-v[u]))

Crossrefs

Cf. A082120, A003681 (starts with 2, 3), A082122.

Sequence in context: A383647 A394286 A281313 * A309622 A215338 A176414

Adjacent sequences: A082118 A082119 A082120 * A082122 A082123 A082124

Keyword

nonn,hard

Author

Ralf Stephan, Apr 04 2003

Extensions

Offset changed and a(14)-a(16) from Sean A. Irvine, Nov 24 2025

Status

approved