A103890 a(n) = prime(n)! / prime(n)# + 1.

2, 2, 5, 25, 17281, 207361, 696729601, 12541132801, 115880067072001, 1366643159020339200001, 40999294770610176000001, 1854768736099424576471040000001, 109950690675973888893203251200000001, 4617929008390903333514536550400000001

Offset: 1

Author

Reinhard Zumkeller, Feb 20 2005

Keywords

• nonn

Links

• Reinhard Zumkeller, p(n)! / p(n)# + 1.

Crossrefs

Cf. A103855, A103891, A103892, A103893, A103894, A103895, A103896.

Programs

Mathematica

#[[1]]/#[[2]]&/@With[{nn=15},Thread[{Prime[Range[nn]]!,FoldList[ Times,Prime[ Range[nn]]]}]]+1 (* Harvey P. Dale, May 21 2019 *)

PARI

a(n) = prime(n)!/vecprod(primes(n)) + 1; \\ Michel Marcus, Nov 12 2023

Formula

a(n) = A039716(n)/A002110(n) + 1 = A092435(n) + 1.