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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A178614 a(n) = prime(n)!/(n+1)!.

Original entry on oeis.org

1, 1, 5, 42, 55440, 1235520, 8821612800, 335221286400, 7124122778572800, 221504779785446277120000, 17166620433372086476800000, 2210327142511928825790332928000000
Offset: 1

Views

Author

Juri-Stepan Gerasimov, Jun 05 2010

Keywords

Programs

  • Magma
    [Factorial(NthPrime(n))/Factorial(n+1): n in [1..15]]; // G. C. Greubel, Jan 29 2019
    
  • Mathematica
    Table[(Prime[n])!/(n+1)!, {n, 1, 15}] (* G. C. Greubel, Jan 29 2019 *)
  • PARI
    vector(15, n, (prime(n))!/(n+1)!) \\ G. C. Greubel, Jan 29 2019
    
  • Sage
    [factorial(nth_prime(n))/factorial(n+1) for n in (1..15)] # G. C. Greubel, Jan 29 2019

Formula

a(n) = A039716(n)/A000142(n+2) = A177946(n)/(n+1).

Extensions

a(7) and a(9) corrected by R. J. Mathar, Jun 07 2010

A181576 Primes whose factorials end with a prime number of trailing 0's.

Original entry on oeis.org

11, 13, 17, 19, 31, 59, 83, 127, 151, 173, 179, 197, 199, 223, 293, 367, 397, 421, 439, 449, 461, 463, 557, 569, 607, 617, 619, 631, 659, 733, 773, 797, 853, 919, 941, 967, 1013, 1039, 1061, 1063, 1087, 1097, 1123, 1181, 1259, 1399, 1423, 1447, 1543, 1567
Offset: 1

Views

Author

Lekraj Beedassy, Nov 02 2010

Keywords

Comments

For the corresponding prime number of trailing end 0's, see A181577.

Examples

			The factorial 2! = 2 ends with 0 zeros, so the prime 2 is not in the sequence because 0 is not a prime.
The factorial 5! = 120 ends with 1 zero, so the prime 5 is not in the sequence because 1 is not a prime.
The factorial 11! = 39916800 ends with 2 zeros, so the prime 11 is in the sequence because 2 is a prime.
		

Crossrefs

Programs

  • Mathematica
    Select[ Prime@ Range@ 250, PrimeQ@ IntegerExponent[ #! ] &] (* Robert G. Wilson v, Nov 06 2010 *)
  • PARI
    is(p) = isprime(p) && isprime((p - sumdigits(p, 5))/4); \\ Amiram Eldar, May 03 2024

Formula

A027868(a(n)) = A181577(n). - Amiram Eldar, May 03 2024

Extensions

More terms from Robert G. Wilson v, Nov 06 2010

A260754 a(n) = prime(n+1)! / prime(n).

Original entry on oeis.org

3, 40, 1008, 5702400, 566092800, 27360571392000, 7155594141696000, 1360632459941314560000, 384424434510421824110592000000, 283546160488893890266398720000000
Offset: 1

Views

Author

Altug Alkan, Aug 20 2015

Keywords

Examples

			a(2) = 5! / 3 = 40.
		

Crossrefs

Programs

Formula

a(n) = prime(n+1)! / prime(n) = A039716(n+1) / A000040(n).
10^(n-1)|a(n+3) for n>=0. - G. C. Greubel, Aug 20 2015

A262206 Product of prime(n) consecutive numbers starting from n.

Original entry on oeis.org

2, 24, 2520, 604800, 54486432000, 53353114214400, 35905578804006912000, 80018147048929689600000, 203939450748460387344384000000, 1441310123089178548721360295690240000000, 9218619547278385997621820451234775040000000
Offset: 1

Views

Author

Altug Alkan, Sep 15 2015

Keywords

Comments

a(n) is always divisible by A039716(n).

Examples

			For n=1, a(1) = 1*2 = 2.
For n=2, a(2) = 2*3*4 = 24.
For n=3, a(3) = 3*4*5*6*7 = 2520.
For n=4, a(4) = 4*5*6*7*8*9*10 = 604800.
		

Crossrefs

Cf. A075069: product of prime(n) consecutive numbers starting from prime(n).

Programs

Formula

a(n) = (prime(n) + n - 1)! / (n-1)!.

A061024 a(n) = (prime(n)!)^2.

Original entry on oeis.org

4, 36, 14400, 25401600, 1593350922240000, 38775788043632640000, 126513546505547170185216000000, 14797530453474819213543604224000000, 668326769467589022464821184293345689600000000, 78176755153939869305210274200729021751146846355456000000000000
Offset: 1

Views

Author

Jason Earls, May 25 2001

Keywords

Crossrefs

Programs

  • Mathematica
    (Prime[Range[10]]!)^2 (* Harvey P. Dale, Mar 22 2020 *)
  • PARI
    { n=0; forprime (p=2, prime(54), write("b061024.txt", n++, " ", p!*p!) ) } \\ Harry J. Smith, Jul 16 2009

Extensions

More terms from Dean Hickerson, Jun 08 2001
Offset corrected by Georg Fischer, Apr 04 2022

A061025 a(n) = prime(n-1)! * prime(n)!.

Original entry on oeis.org

12, 720, 604800, 201180672000, 248562743869440000, 2214873013052296396800000, 43267632904897132203343872000000, 3144771171972468579262286769684480000000, 228577379063395778964892338453378050021130240000000000, 72704382293164078453845555006677990228566567110574080000000000000
Offset: 2

Views

Author

Jason Earls, May 25 2001

Keywords

Crossrefs

Cf. A039716.

Programs

  • Mathematica
    a[n_]:=Prime[n-1]!*Prime[n]!; Array[a,8,2] (* Stefano Spezia, Aug 02 2024 *)
  • PARI
    { n=1; f=2; forprime (p=3, prime(54), g=p!; write("b061025.txt", n++, " ", f*g); f=g ) } \\ Harry J. Smith, Jul 16 2009

Extensions

More terms from Harry J. Smith, Jul 16 2009
Definition offset corrected by Stefano Spezia, Aug 02 2024

A111179 a(n) = Sum_{k=1..n} prime(k)!, where prime(k) is k-th prime.

Original entry on oeis.org

2, 8, 128, 5168, 39921968, 6266942768, 355693695038768, 122000794103870768, 25852138739679080510768, 8841762019591840694222696510768, 8231680416197514658419785576510768, 13763753099458025462513494240000687976510768
Offset: 1

Views

Author

Leroy Quet, Oct 22 2005

Keywords

Examples

			2, 3, 5 and 7 are the first 4 primes. So a(4) = 2! + 3! + 5! + 7! = 2 +6 +120 +5040 = 5168.
		

Crossrefs

Cf. A039716.

Programs

  • Mathematica
    Table[ Sum[ Prime[i]!, {i, n}], {n, 12}] (* Robert G. Wilson v, Oct 28 2005 *)
  • PARI
    a(n)=sum(k=1,n,prime(k)!) \\ Lambert Klasen (lambert.klasen(AT)gmx.net), Oct 28 2005

Extensions

More terms from Lambert Klasen (lambert.klasen(AT)gmx.net) and Robert G. Wilson v, Oct 28 2005

A111180 Product_{k=1..n} prime(k)!.

Original entry on oeis.org

1, 2, 12, 1440, 7257600, 289700167680000, 1803968969906847744000000, 641649083271157094762019815424000000000, 78053467161754909919949074014980107579424768000000000000
Offset: 0

Views

Author

Leroy Quet, Oct 22 2005

Keywords

Examples

			2, 3, 5 and 7 are the first 4 primes. So a(4) = 2! * 3! * 5! * 7! = 2 *6 *120 *5040 = 7257600.
		

Crossrefs

Cf. A039716.

Programs

Extensions

More terms from Robert G. Wilson v, Oct 29 2005

A157132 Factorial of primes divided by prime numbers' respective places in the sequence of primes.

Original entry on oeis.org

2, 3, 40, 1260, 7983360, 1037836800, 50812489728000, 15205637551104000, 2872446304320552960000, 884176199373970195454361600000, 747530786743447528884142080000000
Offset: 1

Views

Author

Jeremy Cahill (jcahill(AT)inbox.com), Feb 23 2009

Keywords

Examples

			E.g. leading term = 2!/1 = 2, second term = 3!/2 = 3, third term = 5!/3 = 40, etc.
		

Crossrefs

Terms of A039716 divided by sequence of natural numbers A000027
Cf. A177946. [From Reinhard Zumkeller, May 15 2010]

Programs

Formula

a(n) = prime(n)!/n.

A181573 Impossible numbers of trailing zeros in the decimal representation of a factorial of any prime.

Original entry on oeis.org

5, 11, 17, 21, 23, 27, 28, 29, 30, 34, 36, 42, 45, 48, 49, 50, 52, 54, 59, 60, 61, 67, 70, 72, 73, 74, 78, 79, 80, 83, 85, 88, 91, 92, 96, 98, 101, 104, 105, 110, 111, 115, 116, 118, 122, 123, 126, 127, 129, 130, 131, 132, 135, 136, 141, 143, 147, 152, 153, 154, 155
Offset: 1

Views

Author

Lekraj Beedassy, Oct 31 2010

Keywords

Comments

No entry of A039716 ends with 5, 11, 17, 21,... consecutive zeros.

Crossrefs

Cf. A000966.

Programs

  • Mathematica
    f[n_] := IntegerExponent[Prime@n!, 10]; Complement[ Range[0, 157], Array[f, 115]] (* Robert G. Wilson v, Nov 05 2010 *)
    zOF[n_Integer?Positive]:=Module[{maxpow=0},While[5^maxpow<=n,maxpow++];Plus@@Table[ Quotient[n,5^i],{i,maxpow-1}]]; Attributes[zOF]={Listable}; With[{z=Union[zOF[Prime[Range[ 150]]]]},Complement[ Range[Max[z]],z]] (* Harvey P. Dale, Sep 17 2024 *)

Extensions

Definition rephrased, keyword:base added by R. J. Mathar, Nov 03 2010
More terms from Robert G. Wilson v, Nov 05 2010
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