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.

Showing 1-8 of 8 results.

A104344 a(n) = Sum_{k=1..n} k!^2.

Original entry on oeis.org

1, 5, 41, 617, 15017, 533417, 25935017, 1651637417, 133333531817, 13301522971817, 1606652445211817, 231049185247771817, 39006837228880411817, 7639061293780877851817, 1717651314017980301851817, 439480788011413032845851817, 126953027293558583218061851817
Offset: 1

Views

Author

Eric W. Weisstein, Mar 02 2005

Keywords

Crossrefs

Sum_{k=1..n} (k!)^m: A007489 (m=1), this sequence (m=2), A138564 (m=3), A289945 (m=4), A316777 (m=5), A289946 (m=6).

Programs

  • Mathematica
    Table[Sum[(k!)^2,{k,n}],{n,15}] (* Harvey P. Dale, Jul 21 2011 *)
    Accumulate[(Range[20]!)^2] (* Much more efficient than the above program. *) (* Harvey P. Dale, Aug 15 2022 *)
  • PARI
    a(n) = sum(k=1, n, k!^2); \\ Michel Marcus, Jul 16 2017

Formula

a(n) = A061062(n) - 1. - Michel Marcus, Feb 28 2014

Extensions

More terms from Vladimir Joseph Stephan Orlovsky, Sep 24 2009

A100289 Numbers k such that (1!)^2 + (2!)^2 + (3!)^2 + ... + (k!)^2 is prime.

Original entry on oeis.org

2, 3, 4, 5, 7, 8, 10, 18, 21, 42, 51, 91, 133, 177, 182, 310, 3175, 9566, 32841
Offset: 1

Views

Author

T. D. Noe, Nov 11 2004 and Dec 11 2004

Keywords

Comments

All k <= 310 yield provable primes.
Write the sum as S(2,k)-1, where S(m,k) = Sum_{i=0..k} (i!)^m. Let p=1248829. Because p divides S(2,p-1)-1, p divides S(2,k)-1 for all k >= p-1. Hence there are no primes for k >= p-1.

Crossrefs

Cf. A100288 (primes of the form (1!)^2 + (2!)^2 + (3!)^2 +...+ (k!)^2).
Cf. A061062 ((0!)^2 + (1!)^2 + (2!)^2 + (3!)^2 +...+ (n!)^2).
Cf. A289947 (k!^6), A290014 (k!^10).
Cf. also A104344.

Programs

Extensions

a(18) from T. D. Noe, Feb 15 2006
a(19) from Serge Batalov, Jul 29 2017

A100288 Primes of the form (1!)^2 + (2!)^2 + (3!)^2 +...+ (k!)^2.

Original entry on oeis.org

5, 41, 617, 15017, 25935017, 1651637417, 13301522971817, 41117342095090841723228045851817, 2616218222822143606864564493635469851817
Offset: 1

Views

Author

T. D. Noe, Nov 11 2004

Keywords

Comments

Jonathan Vos Post contributed these numbers to Prime Curios.

Examples

			41 = (1!)^2 + (2!)^2 + (3!)^2 is prime.
		

Crossrefs

Cf. A100289 (k such that (1!)^2 + (2!)^2 + (3!)^2 + ... + (k!)^2 is prime).
See also A061062, A104344.

Programs

  • Mathematica
    Select[Accumulate[Table[(n!)^2,{n,30}]],PrimeQ] (* Harvey P. Dale, May 09 2025 *)
  • PARI
    lista(nn) = {my(s=1); for(k=2, nn, s+=(k!)^2; if(ispseudoprime(s), print1(s, ", "))); } \\ Jinyuan Wang, Mar 08 2020

A101746 Primes of the form ((0!)^2+(1!)^2+(2!)^2+...+(n!)^2)/6.

Original entry on oeis.org

7, 103, 2503, 88903, 4322503, 2473107965928318342544472044975303
Offset: 1

Views

Author

T. D. Noe, Dec 18 2004

Keywords

Comments

Let S(n)=sum_{i=0,..n-1} (i!)^2. Note that 6 divides S(n) for n>1. For prime p=20879, p divides S(p-1). Hence p divides S(n) for all n >= p-1 and all prime values of S(n)/6 are for n < p-1.
The next term (a(7)) has 96 digits. The largest term (a(9)) has 288 digits. - Harvey P. Dale, Aug 31 2021

Crossrefs

Cf. A061062 (S(n)), A100288 (primes of the form S(n)-1), A100289 (n such that S(n)-1 is prime), A101747 (n such that S(n)/6 is prime).

Programs

  • Mathematica
    f2=1; s=2; Do[f2=f2*n*n; s=s+f2; If[PrimeQ[s/6], Print[{n, s/6}]], {n, 2, 100}]
    Select[Accumulate[(Range[0,25]!)^2]/6,PrimeQ] (* Harvey P. Dale, Aug 31 2021 *)

A289948 a(n) = Sum_{k=0..n} k!^3.

Original entry on oeis.org

1, 2, 10, 226, 14050, 1742050, 374990050, 128399054050, 65676719822050, 47850402559694050, 47832576242431694050, 63649302669112063694050, 109966989623147836159694050, 241567605673714904675071694050, 662801328154821495670649599694050, 2236801993181528581580834681599694050
Offset: 0

Views

Author

Seiichi Manyama, Jul 16 2017

Keywords

Crossrefs

Cf. A003422(n+1) (k!), A061062 (k!^2), this sequence (k!^3), A289949 (k!^4).

Programs

  • Mathematica
    With[{nn = 16}, Table[Total@ Take[#, n], {n, nn}] &@ Table[k!^3, {k, 0, nn}]] (* Michael De Vlieger, Jul 16 2017 *)
    Accumulate[(Range[0,20]!)^3] (* Harvey P. Dale, Nov 30 2017 *)
  • PARI
    a(n) = sum(k=0, n, k!^3); \\ Michel Marcus, Jul 16 2017

A289949 a(n) = Sum_{k=0..n} k!^4.

Original entry on oeis.org

1, 2, 18, 1314, 333090, 207693090, 268946253090, 645510228813090, 2643553803594573090, 17342764866576345933090, 173418555892594089945933090, 2538940579958951120707545933090, 52646414799433780559063261145933090, 1503614384819523432725006336630745933090
Offset: 0

Views

Author

Seiichi Manyama, Jul 16 2017

Keywords

Crossrefs

Cf. A289945.
Sum_{k=0..n} k!^m: A003422(n+1) (m=1), A061062 (m=2), A289948 (m=3), this sequence (m=4).

Programs

  • Mathematica
    Accumulate[(Range[0,15]!)^4] (* Harvey P. Dale, Nov 29 2020 *)
  • PARI
    a(n) = sum(k=0, n, k!^4); \\ Michel Marcus, Jul 16 2017

Formula

a(n) = A289945(n) + 1 for n > 0.

A101747 Numbers n such that ((0!)^2+(1!)^2+(2!)^2+...+(n!)^2)/6 is prime.

Original entry on oeis.org

3, 4, 5, 6, 7, 19, 40, 56, 93
Offset: 1

Views

Author

T. D. Noe, Dec 18 2004

Keywords

Comments

Let S(n) = Sum_{i=0,..n-1} (i!)^2. Note that 6 divides S(n) for n>1. For prime p=20879, p divides S(p-1). Hence p divides S(n) for all n >= p-1 and all prime values of S(n)/6 are for n < p-1. These n yield provable primes for n <= 93. No other n < 4000.
No other n < 8000. [T. D. Noe, Jul 31 2008]

Crossrefs

Cf. A061062 (S(n)), A100288 (primes of the form S(n)-1), A100289 (n such that S(n)-1 is prime), A101746 (primes of the form S(n)/6).

Programs

  • Mathematica
    f2=1; s=2; Do[f2=f2*n*n; s=s+f2; If[PrimeQ[s/6], Print[{n, s/6}]], {n, 2, 100}]

A173476 Triangle T(n, k) = 1 + (k!)^2 - 2*k!*(n-k)! + ((n-k)!)^2, read by rows.

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 26, 2, 2, 26, 530, 26, 1, 26, 530, 14162, 530, 17, 17, 530, 14162, 516962, 14162, 485, 1, 485, 14162, 516962, 25391522, 516962, 13925, 325, 325, 13925, 516962, 25391522, 1625621762, 25391522, 515525, 12997, 1, 12997, 515525, 25391522, 1625621762
Offset: 0

Views

Author

Roger L. Bagula, Feb 19 2010

Keywords

Examples

			Triangle begins as:
           1;
           1,        1;
           2,        1,      2;
          26,        2,      2,    26;
         530,       26,      1,    26, 530;
       14162,      530,     17,    17, 530, 14162;
      516962,    14162,    485,     1, 485, 14162, 516962;
    25391522,   516962,  13925,   325, 325, 13925, 516962, 25391522;
  1625621762, 25391522, 515525, 12997,   1, 12997, 515525, 25391522, 1625621762;
		

Crossrefs

Programs

  • Magma
    [(Factorial(n-k) -Factorial(k))^2 +1: k in [0..n], n in [0..12]]; // G. C. Greubel, Feb 19 2021
  • Mathematica
    Table[((n-k)! -k!)^2 +1, {n,0,12}, {k,0,n}]//Flatten (* modified by G. C. Greubel, Feb 19 2021 *)
  • Sage
    flatten([[(factorial(n-k) -factorial(k))^2 +1 for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Feb 19 2021
    

Formula

T(n, k) = 1 + ( (n-k)! - k! )^2.
Sum_{k=0..n} T(n, k) = 1 + n + 2*A061062(n) - 2*A003149(n). - G. C. Greubel, Feb 19 2021

Extensions

Edited by G. C. Greubel, Feb 19 2021
Showing 1-8 of 8 results.