cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A139161 a(n)=(prime(n)!+3)/3.

Original entry on oeis.org

3, 41, 1681, 13305601, 2075673601, 118562476032001, 40548366802944001, 8617338912961658880001, 2947253997913233984847872000001, 2740946218059307605908520960000001
Offset: 2

Views

Author

Artur Jasinski, Apr 11 2008

Keywords

Crossrefs

Programs

  • Mathematica
    Table[(Prime[n]! + 3)/3, {n, 2, 30}]

A139072 Smallest parameter k such that (n+k!)/n is prime.

Original entry on oeis.org

1, 2, 3, 4, 7, 3, 11, 7, 8, 5, 13, 4, 28, 10, 7, 8, 43, 6, 21, 5, 7, 16, 48, 4, 14, 17, 9, 7, 241, 5, 61, 11, 17, 17, 8, 10, 44, 38, 16, 6, 131, 9, 63, 12, 6, 43, 73, 9, 15, 10, 19, 14, 64, 11, 12, 9, 24, 32, 641, 5, 89, 31, 8, 8, 14, 11, 71, 19, 25, 7, 151, 6, 78, 62, 15, 35, 15, 22, 87
Offset: 1

Views

Author

Artur Jasinski, Apr 07 2008

Keywords

Comments

a(n) >= A002034(n). - Charles R Greathouse IV, Jul 15 2011
a(878) > 5000. - Jinyuan Wang, Apr 01 2020

Crossrefs

Programs

  • Mathematica
    a = {}; Do[k = 1; While[ ! PrimeQ[(k! + n)/n], k++ ]; AppendTo[a, k], {n, 1, 100}]; a
  • PARI
    pr(n)=denominator(n)==1 && ispseudoprime(n)
    a(n)=my(k);until(pr(k++!/n+1),);k \\ Charles R Greathouse IV, Jul 15 2011

A139074 a(n) = smallest prime p such that p!/n + 1 is prime, or 0 if no such prime exists.

Original entry on oeis.org

2, 2, 3, 5, 7, 3, 11, 7, 26737, 5, 13, 5
Offset: 1

Views

Author

Artur Jasinski, Apr 08 2008, Apr 21 2008

Keywords

Comments

For the corresponding primes p see A139075.
a(9)>5000, a(13)>5000, a(22)>5000, a(23) = 1579. - Andrew V. Sutherland, Apr 21 2008, Apr 22 2008
a(10)=5, a(11)=13, a(12)=5
a(14)=17, a(15)=7, a(16)=13, a(17)=43, a(18)=7,
a(19)=31, a(20)=5, a(21)=7
a(24)=7, a(25)=47, a(26)=17, a(27)=17, a(28)=7,
a(29)=241, a(30)=5, a(31)=61, a(32)=11, a(33)=17,
a(34)=17, a(35)=29, a(36)=11, a(37)=61, a(38)=103,
a(39)=89, a(40)=7, a(41)=131, a(42)=11, a(43)=71,
a(44)=13, a(45)=7, a(46)=43, a(47)=73, a(48)=67,
a(49)=347, a(50)=31, a(51)=19, a(52)=17, a(53)=347,
a(54)=11, a(55)=13, a(56)=13, a(57)=31, a(58)=73,
a(59)=641, a(60)=5
a(23) = 1579. - Andrew V. Sutherland, Apr 11 2008.
Smallest daughter factorial prime p of order n, i.e. smallest prime of the form (p!+n)/n where p is prime.
For smallest mother factorial prime p of order n see A139075
For smallest father factorial prime p of order n see A139207
For smallest son factorial prime p of order n see A139206
Summary added by Robert Price, Nov 25 2010:
a(1:20)=2,2,3,5,7,3,11,7,26737,5,13,5,>60000,17,7,13,43,7,31,5
a(21:40)=7,>60000,1579,7,47,17,17,7,241,5,61,11,17,17,29,11,61,103,89,7
a(41:60)=131,11,71,13,7,43,73,67,347,31,19,17,347,11,13,13,31,73,641,5
a(61:80)=89,31,13,13,17,11,71,19,131,7,151,7,>10000,641,73,43,17,331,113,11
a(81:100)=13,67,>10000,7,1999,89,31,11,>10000,19,19,31,607,71,61,11,761,23,>10000,83

Examples

			a(1) = 2 because 2 is the first prime and 2!/1 + 1 = 3 is prime
a(2) = 2 because 2 is the first prime and 2!/2 + 1 = 2 is prime
a(3) = 3 because 3!/3 + 1 = 3 is prime
		

Crossrefs

Programs

  • Mathematica
    a = {}; Do[k = 1; While[ ! PrimeQ[(Prime[k]! + n)/n], k++ ]; AppendTo[a, Prime[k]], {n, 1, 8}]; a

Extensions

a(9)-a(12) by Robert Price, Dec 19 2010

A139156 a(n) = (n!+9)/9.

Original entry on oeis.org

81, 561, 4481, 40321, 403201, 4435201, 53222401, 691891201, 9686476801, 145297152001, 2324754432001, 39520825344001, 711374856192001, 13516122267648001, 270322445352960001, 5676771352412160001
Offset: 6

Views

Author

Artur Jasinski, Apr 11 2008

Keywords

Crossrefs

Programs

  • Mathematica
    Table[(n! + 9)/9, {n, 6, 30}]

Extensions

Name corrected by Amiram Eldar, Oct 14 2024

A139092 a(n) = number of distinct prime divisors of (9+prime(n)!)/9.

Original entry on oeis.org

3, 3, 2, 2, 2, 3, 2, 3, 4, 4, 5, 3, 3, 6, 5, 2, 3, 4, 3, 3, 4, 4, 4, 3, 7, 3, 3
Offset: 4

Views

Author

Artur Jasinski, Apr 08 2008

Keywords

Comments

Conjecture: all prime divisors in A139089 are distinct
a(31) >= 4. - Amiram Eldar, Feb 13 2020

Crossrefs

Programs

  • Mathematica
    a = {}; Do[w = (Prime[n]! + 9)/9; AppendTo[a, w], {n, 4, 16}]; a
    PrimeNu[(9+Prime[Range[4,25]]!)/9] (* Harvey P. Dale, Jul 25 2019 *)

Formula

a(n) = A001221(A139089(n)). - Amiram Eldar, Feb 13 2020

Extensions

More terms from Jon E. Schoenfield, Jul 16 2010
a(23)-a(30) using factordb.com from Amiram Eldar, Feb 13 2020

A139149 a(n) = (n!+2)/2.

Original entry on oeis.org

2, 4, 13, 61, 361, 2521, 20161, 181441, 1814401, 19958401, 239500801, 3113510401, 43589145601, 653837184001, 10461394944001, 177843714048001, 3201186852864001, 60822550204416001, 1216451004088320001, 25545471085854720001, 562000363888803840001
Offset: 2

Views

Author

Artur Jasinski, Apr 11 2008

Keywords

Comments

Also the number of (not necessarily maximal) cliques in the (n-1)-(weak) Bruhat graph. - Eric W. Weisstein, Jul 29 2018

Examples

			(1!+2)/2 = 3/2 is not an integer.
a(2) = (2!+2)/2 = 2.
		

Crossrefs

a(n) = (n!+m)/m: A038507 (m=1), this sequence (m=2), A139150 (m=3), A139151 (m=4), A139152 (m=5), A139153 (m=6), A139154 (m=7), A139155 (m=8), A139156 (m=9), A139157 (m=10).
Offsets for above sequences are Kempner numbers A002034.
For smallest number of the form (m!+n)/n see A139148.

Programs

A139150 a(n) = (n!+3)/3.

Original entry on oeis.org

3, 9, 41, 241, 1681, 13441, 120961, 1209601, 13305601, 159667201, 2075673601, 29059430401, 435891456001, 6974263296001, 118562476032001, 2134124568576001, 40548366802944001, 810967336058880001
Offset: 3

Views

Author

Artur Jasinski, Apr 11 2008

Keywords

Examples

			(2!+3)/3 = 5/3 is not an integer.
a(3) = (3!+3)/3 = 3.
		

Crossrefs

Programs

  • Mathematica
    Table[(n! + 3)/3, {n, 3, 30}]

Extensions

Name corrected by Amiram Eldar, Oct 13 2024

A139152 a(n) = (n!+5)/5.

Original entry on oeis.org

25, 145, 1009, 8065, 72577, 725761, 7983361, 95800321, 1245404161, 17435658241, 261534873601, 4184557977601, 71137485619201, 1280474741145601, 24329020081766401, 486580401635328001, 10218188434341888001
Offset: 5

Views

Author

Artur Jasinski, Apr 11 2008

Keywords

Crossrefs

Programs

  • Mathematica
    Table[(n! + 5)/5, {n, 5, 30}]

Extensions

Name corrected by Amiram Eldar, Oct 14 2024

A139153 a(n) = (n!+6)/6.

Original entry on oeis.org

2, 5, 21, 121, 841, 6721, 60481, 604801, 6652801, 79833601, 1037836801, 14529715201, 217945728001, 3487131648001, 59281238016001, 1067062284288001, 20274183401472001, 405483668029440001, 8515157028618240001
Offset: 3

Views

Author

Artur Jasinski, Apr 11 2008

Keywords

Crossrefs

Programs

  • Mathematica
    Table[(n! + 6)/6, {n, 3, 30}]

Extensions

Name corrected by Amiram Eldar, Oct 14 2024

A139154 a(n) = (n!+7)/7.

Original entry on oeis.org

721, 5761, 51841, 518401, 5702401, 68428801, 889574401, 12454041601, 186810624001, 2988969984001, 50812489728001, 914624815104001, 17377871486976001, 347557429739520001, 7298706024529920001
Offset: 7

Views

Author

Artur Jasinski, Apr 11 2008

Keywords

Crossrefs

Programs

  • Mathematica
    Table[(n! + 7)/7, {n, 7, 30}]

Extensions

Name corrected by Amiram Eldar, Oct 14 2024
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