A103895 -id:A103895 - 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.

A103860 Sum of divisors of prime(n)! - prime(n)# + 1.

Original entry on oeis.org

1, 1, 112, 4832, 39929032, 6227388000, 355687500698712, 121674349040732800, 26204303786955547121568, 8844022735747817449795273936944, 8243360285859647409507002537385024, 13989390090648918627329493090109449081402880, 33452526614068666040537953433982904696696861440000

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. A000203, A103855, A103858, A103859, A103895.

Module[{nn=15,pr,pm},pr=Prime[Range[nn]]!;pm=FoldList[Times,Prime[Range[nn]]];DivisorSigma[1,#[[1]]-#[[2]]+1&/@Thread[{pr,pm}]]] (* Harvey P. Dale, Dec 18 2022 *)

a(n) = sigma(prime(n)! - factorback(primes(n)) + 1); \\ Jinyuan Wang, Dec 28 2024

a(n) = A000203(A103855(n)).

A103894 Number of divisors of prime(n)! / prime(n)# + 1.

Original entry on oeis.org

2, 2, 2, 3, 4, 8, 8, 16, 4, 8, 4, 16, 16, 32, 8, 4, 8, 16, 64, 32, 32, 32, 32, 64, 32, 16, 32, 8, 128, 32

Offset: 1

Reinhard Zumkeller, Feb 20 2005

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

Cf. A000005, A103859, A103890, A103895.

a(n) = A000005(A103890(n)).

a(28)-a(30) from Amiram Eldar, Feb 13 2020

cp's OEIS Frontend

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

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A103860 Sum of divisors of prime(n)! - prime(n)# + 1.

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Author

Keywords

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Programs

Mathematica

PARI

Formula

A103894 Number of divisors of prime(n)! / prime(n)# + 1.

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