A103891 -id:A103891 - 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.

A103856 Smallest prime factor of prime(n)! - prime(n)# + 1.

Original entry on oeis.org

1, 1, 7, 4831, 3673, 16349, 5240507, 4159, 83, 3911, 401, 61, 66935021479, 199, 73, 152249, 379, 5014363, 181, 191, 277, 155893, 35851, 431, 1499

Offset: 1

Reinhard Zumkeller, Feb 20 2005

nonn

a(26) has 160 digits and is too large to be included here.

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

Cf. A020639, A103855, A103857, A103891.

a(n) = if(n>2, factor(prime(n)!-factorback(primes(n))+1)[1, 1], 1); \\ Jinyuan Wang, Dec 30 2024

a(n) = A020639(A103855(n)).

A103892 Greatest prime factor of prime(n)! / prime(n)# + 1.

Original entry on oeis.org

2, 2, 5, 5, 1571, 2693, 15427, 27749, 4154449757, 151585363459003, 73899633146196133, 24770877398207, 1429176066859677377, 7748318379505746557, 21662673895172922098651, 447620901583917369406703727865417431168683, 26823894708473887265117477378744683922119

Offset: 1

Reinhard Zumkeller, Feb 20 2005

nonn

Amiram Eldar, Table of n, a(n) for n = 1..30
Reinhard Zumkeller, prime(n)! / prime(n)# + 1.

Cf. A006530, A103857, A103890, A103891.

a(n) = A006530(A103890(n)).

cp's OEIS Frontend

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

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A103856 Smallest prime factor of prime(n)! - prime(n)# + 1.

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PARI

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A103892 Greatest prime factor of prime(n)! / prime(n)# + 1.

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Author

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