A139090 a(n) = smallest prime divisor of the number prime(n)!/9 + 1.

3, 31, 31, 23, 379, 83, 610301, 293, 101, 47, 281, 127, 278174297, 2971, 109, 5090615254324820333, 46411, 106087, 269, 288931, 59047158151, 120871, 373, 19140822523, 56595118147, 1708207, 331, 38749, 157, 2927, 2143

Offset: 4

Author

Artur Jasinski, Apr 08 2008

Keywords

• more
• nonn

Crossrefs

Cf. A082672, A089085, A089130, A117141, A007749, A139056-A139066, A020458, A139068, A137390, A139070-A139075, A136019, A136020, A136026, A136027, A139089-A139092.

Programs

Mathematica

a = {}; Do[w = FactorInteger[(Prime[n]! + 9)/9]; AppendTo[a, First[w][[1]]], {n, 4, 16}]; a
Table[FactorInteger[p!/9+1][[1,1]],{p,Prime[Range[4,35]]}] (* Harvey P. Dale, Sep 19 2020 *)

Extensions

More terms from Jon E. Schoenfield, Jul 16 2010