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 1-10 of 77 results. Next

A114796 Cumulative product of sextuple factorial A085158.

Original entry on oeis.org

1, 1, 2, 6, 24, 120, 720, 5040, 80640, 2177280, 87091200, 4790016000, 344881152000, 31384184832000, 7030057402368000, 2847173247959040000, 1822190878693785600000, 1703748471578689536000000
Offset: 0

Views

Author

Jonathan Vos Post, Feb 18 2006

Keywords

Examples

			a(10) = 1!6 * 2!6 * 3!6 * 4!6 * 5!6 * 6!6 * 7!6 * 8!6 * 9!6 * 10!6
= 1 * 2 * 3 * 4 * 5 * 6 * 7 * 16 * 27 * 40 = 87091200 = 2^11 * 3^5 * 5^2 * 7.
Note that a(10) + 1 = 87091201 is prime, as is a(9) + 1 = 2177281.
		

Crossrefs

Programs

  • GAP
    b:= function(n)
        if n<1 then return 1;
        else return n*b(n-6);
        fi;
      end;
    List([0..20], n-> Product([0..n], j-> b(j)) ); # G. C. Greubel, Aug 22 2019
  • Magma
    b:=func< n | n le 6 select n else n*Self(n-6) >;
    [1] cat [(&*[b(j): j in [1..n]]): n in [1..20]]; // G. C. Greubel, Aug 22 2019
    
  • Maple
    b:= n-> `if`(n<1, 1, n*b(n-5)); a:= n-> product(b(j), j = 0..n); seq(a(n), n = 0..20); # G. C. Greubel, Aug 22 2019
  • Mathematica
    b[n_]:= b[n]= If[n<1, 1, n*b[n-6]]; a[n_]:= Product[b[j], {j,0,n}];
    Table[a[n], {n, 0, 20}] (* G. C. Greubel, Aug 22 2019 *)
  • PARI
    b(n)=if(n<1, 1, n*b(n-6));
    vector(20, n, n--; prod(j=0,n, b(j)) ) \\ G. C. Greubel, Aug 22 2019
    
  • Sage
    def b(n):
        if (n<1): return 1
        else: return n*b(n-6)
    [product(b(j) for j in (0..n)) for n in (0..20)] # G. C. Greubel, Aug 22 2019
    

Formula

a(n) = Product_{j=0..n} j!!!!!!.
a(n) = Product_{j=0..n} j!6.
a(n) = Product_{j=0..n} A085158(j).
a(n) = n!!!!!! * a(n-1) where a(0) = 1, a(1) = 1 and n >= 2.
a(n) = n*(n-6)!!!!!! * a(n-1) where a(0) = 1, a(1) = 1, a(2) = 2.

A279646 Numbers k such that k!6 - 3 is prime, where k!6 is the sextuple factorial number (A085158).

Original entry on oeis.org

5, 6, 8, 10, 68, 82, 92, 98, 118, 286, 796, 878, 1360, 1502, 1516, 1568, 1646, 3628, 3716, 4048, 7982, 12776, 18070, 20594, 29902, 39632, 52988, 53864, 55610, 67448, 85402, 89762
Offset: 1

Views

Author

Robert Price, Jul 07 2017

Keywords

Comments

Corresponding primes are: 2, 3, 13, 37, 73569236156415997, ...
a(33) > 10^5.
Terms > 10 correspond to probable primes.

Examples

			10!6 - 3 = 10*4 - 3 = 37 is prime, so 10 is in the sequence.
		

Crossrefs

Programs

  • Mathematica
    MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
    Select[Range[4, 50000], PrimeQ[MultiFactorial[#, 6] - 3] &]

Extensions

a(27)-a(32) from Robert Price, Aug 03 2018

A283485 Numbers k such that k![6]-2 is prime, where k![6] = A085158 (k) = sextuple factorial.

Original entry on oeis.org

4, 5, 7, 11, 13, 23, 25, 31, 33, 37, 59, 63, 91, 157, 265, 267, 327, 539, 555, 621, 715, 921, 979, 1633, 1821, 2259, 2697, 2809, 2863, 2935, 4213, 4351, 5937, 6885, 8743, 10761, 15159, 17685, 52075, 55147, 68677, 99655
Offset: 1

Views

Author

Robert Price, Mar 08 2017

Keywords

Comments

a(43) > 10^5.
The first 10 primes associated with this sequence: 2, 3, 5, 53, 89, 21503, 43223, 1339973, 7577953, 49579073.

Crossrefs

Programs

  • Mathematica
    MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
    Select[Range[2, 50000], PrimeQ[MultiFactorial[#, 6] - 2] &]
    Select[Range[100000],PrimeQ[Times@@Range[#,1,-6]-2]&] (* Harvey P. Dale, Feb 23 2023 *)

Extensions

a(39)-a(42) from Robert Price, Jul 09 2017

A287207 Numbers k such that k![6] + 2 is prime, where k![6] = A085158(k) = sextuple factorial.

Original entry on oeis.org

0, 1, 3, 5, 9, 17, 27, 45, 51, 53, 93, 197, 213, 221, 245, 279, 845, 927, 2055, 2895, 3615, 5613, 12753, 15737, 17813, 18545, 22629, 47859, 48797
Offset: 1

Views

Author

Robert Price, May 21 2017

Keywords

Comments

a(30) > 50000.
The first 7 primes associated with this sequence: 3, 3, 5, 7, 29, 937, 229637.

Crossrefs

Programs

  • Mathematica
    MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
    Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 6] + 2] &]
    Select[Range[0,10000],PrimeQ[Times@@Range[#,1,-6]+2]&] (* The program generates the first 22 terms of the sequence. *) (* Harvey P. Dale, Dec 27 2022 *)

A287844 Numbers k such that k!6 + 3 is prime, where k!6 is the sextuple factorial number (A085158 ).

Original entry on oeis.org

2, 4, 8, 10, 14, 16, 20, 22, 26, 34, 70, 164, 346, 398, 902, 938, 1426, 1682, 1928, 3596, 3796, 15058, 25654, 37330
Offset: 1

Views

Author

Robert Price, Jun 01 2017

Keywords

Comments

Corresponding primes are: 5, 7, 19, 43, 227, 643, 4483, 14083, 116483, 13404163, ...
a(25) > 50000.
Terms > 34 correspond to probable primes.

Examples

			10!6 + 3 = 10*4 + 3 = 43 is prime, so 10 is in the sequence.
		

Crossrefs

Programs

  • Mathematica
    MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
    Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 6] + 3] &]
    Select[Range[3800],PrimeQ[Times@@Range[#,1,-6]+3]&] (* The program generates the first 21 terms of the sequence. *) (* Harvey P. Dale, May 23 2025 *)

A287914 Numbers k such that k!6 + 4 is prime, where k!6 is the sextuple factorial number (A085158 ).

Original entry on oeis.org

1, 3, 7, 9, 11, 15, 19, 27, 35, 59, 71, 75, 95, 109, 153, 155, 169, 189, 277, 355, 383, 405, 455, 625, 843, 853, 879, 1389, 1423, 1515, 1871, 2059, 2677, 3095, 4473, 5691, 5927, 8149, 10789, 12171, 14683, 26383, 34227, 40945
Offset: 1

Views

Author

Robert Price, Jun 02 2017

Keywords

Comments

Corresponding primes are: 5, 7, 11, 31, 59, 409, 1733, 229639, 21827579, ...
a(45) > 50000.
Terms > 35 correspond to probable primes.

Examples

			11!6 + 4 = 11*5 + 4 = 59 is prime, so 11 is in the sequence.
		

Crossrefs

Programs

  • Mathematica
    MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
    Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 6] + 4] &]

A287956 Numbers k such that k!6 + 6 is prime, where k!6 is the sextuple factorial number (A085158 ).

Original entry on oeis.org

1, 5, 7, 11, 13, 17, 37, 43, 55, 107, 139, 149, 157, 211, 223, 343, 373, 409, 523, 12049, 16457, 17143, 17543, 18391, 25829, 25945, 31307, 34601, 41687
Offset: 1

Views

Author

Robert Price, Jun 03 2017

Keywords

Comments

Corresponding primes are: 7, 11, 13, 61, 97, 941, 49579081, 2131900231, 5745471106381, ...
a(43) > 50000.
Terms > 35 correspond to probable primes.

Examples

			11!6 + 6 = 11*5 + 6 = 61 is prime, so 11 is in the sequence.
		

Crossrefs

Programs

  • Mathematica
    MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
    Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 6] + 6] &]

A288152 Numbers k such that k!6 + 8 is prime, where k!6 is the sextuple factorial number (A085158 ).

Original entry on oeis.org

3, 5, 21, 29, 41, 65, 243, 305, 389, 509, 819, 1653, 7493, 8613, 8619, 10257, 11829, 12977, 15651, 24341, 29367, 31629, 40173
Offset: 1

Views

Author

Robert Price, Jun 05 2017

Keywords

Comments

Corresponding primes are: 11, 13, 8513, 623653, 894930583, 8549258359016383, ...
a(24) > 50000.
Terms > 41 correspond to probable primes.

Examples

			21!6 + 8 = 21*15*9*3 + 8 = 8513 is prime, so 21 is in the sequence.
		

Crossrefs

Programs

  • Mathematica
    MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
    Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 6] + 8] &]

A288154 Numbers k such that k!6 + 9 is prime, where k!6 is the sextuple factorial number (A085158 ).

Original entry on oeis.org

2, 4, 14, 28, 34, 46, 50, 52, 86, 100, 106, 140, 166, 170, 208, 242, 338, 344, 412, 1360, 2024, 2948, 3650, 5608, 5744, 7618, 8410, 8834, 11872, 12514, 13636, 18742, 20846, 29750, 31312
Offset: 1

Views

Author

Robert Price, Jun 05 2017

Keywords

Comments

Corresponding primes are: 11, 13, 233, 394249, 13404169, 24663654409, 311607296009, ...
a(36) > 50000.
Terms > 50 correspond to probable primes.

Examples

			14!6 + 9 = 14*8*2 + 9 = 233 is prime, so 14 is in the sequence.
		

Crossrefs

Programs

  • Mathematica
    MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
    Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 6] + 9] &]

A288155 Numbers k such that k!6 + 12 is prime, where k!6 is the sextuple factorial number (A085158 ).

Original entry on oeis.org

0, 1, 5, 7, 11, 13, 17, 19, 23, 25, 41, 67, 71, 101, 109, 151, 163, 181, 233, 241, 265, 355, 433, 563, 767, 997, 1465, 1681, 1861, 1913, 2411, 2539, 2777, 13433, 22355, 30895, 44605
Offset: 1

Views

Author

Robert Price, Jun 05 2017

Keywords

Comments

Corresponding primes are: 13, 13, 17, 19, 67, 103, 947, 1741, 21517, 43237, 894930587, ...
a(37) > 50000.
Terms > 41 correspond to probable primes.

Examples

			11!6 + 12 = 11*5 + 12 = 67 is prime, so 11 is in the sequence.
		

Crossrefs

Programs

  • Mathematica
    MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
    Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 6] + 12] &]
    Select[Range[0, 45000], PrimeQ[Times @@ Range[#, 1, -6] + 12] &] (* Harvey P. Dale, Jul 09 2020 *)
Showing 1-10 of 77 results. Next