A103896 -id:A103896 - cp's OEIS frontend

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

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

Offset: 1

Reinhard Zumkeller, Feb 20 2005

nonn

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

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

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

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

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

A103861 Euler's totient of prime(n)! - prime(n)# + 1.

Original entry on oeis.org

1, 1, 72, 4830, 39899952, 6226593544, 355687354472272, 121615851757531824, 25500701524255140352000, 8839501251731586459279018676600, 8202317101101304783411826869132800, 13538116146734258320615004890482768163319520, 33452526612258948175814325380737291579993833222336

Offset: 1

Reinhard Zumkeller, Feb 20 2005

nonn

Amiram Eldar, Table of n, a(n) for n = 1..26
Reinhard Zumkeller, p(n)! - p(n)# + 1.

Cf. A000010, A103855, A103896.

EulerPhi[Table[Prime[n]! - Product[Prime[i], {i, 1, n}] + 1, {n, 1, 10}]] (* Amiram Eldar, Feb 21 2020 *)

a(n) = A000010(A103855(n)).

cp's OEIS Frontend

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

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