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 63 results. Next

A283553 Numbers k such that k![4] + 2 is prime, where k![4] = A007662(k) = quadruple factorial.

Original entry on oeis.org

0, 1, 3, 5, 7, 9, 11, 13, 15, 19, 27, 29, 31, 43, 53, 75, 143, 169, 185, 235, 259, 363, 365, 457, 493, 573, 777, 1273, 1275, 1865, 3621, 4523, 5291, 5845, 7185, 10183, 12845, 15057, 16281, 17945, 18771, 22479, 27235, 28089, 31557, 39163, 45709, 46329, 52211, 77779
Offset: 1

Views

Author

Robert Price, Mar 10 2017

Keywords

Comments

a(51) > 10^5.
The first 10 primes associated with this sequence: 3, 3, 5, 7, 23, 47, 233, 587, 3467, 65837.

Crossrefs

Programs

  • Mathematica
    MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
    Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 4] + 2] &]
    Select[Range[0,78000],PrimeQ[Times@@Range[#,1,-4]+2]&] (* Harvey P. Dale, Aug 16 2023 *)

Extensions

a(49)-a(50) from Robert Price, Aug 12 2017

A114779 Cumulative product of quadruple factorial A007662.

Original entry on oeis.org

1, 1, 2, 6, 24, 120, 1440, 30240, 967680, 43545600, 5225472000, 1207084032000, 463520268288000, 271159356948480000, 455547719673446400000, 1578472848668491776000000, 9698137182219213471744000000
Offset: 0

Views

Author

Jonathan Vos Post, Feb 18 2006

Keywords

Examples

			a(10) = 1!!!! * 2!!!! * 3!!!! * 4!!!! * 5!!!! * 6!!!! * 7!!!! * 8!!!! * 9!!!! * 10!!!! = 1 * 2 * 3 * 4 * 5 * 12 * 21 * 32 * 45 * 120 = 5225472000 = 2^13 * 3^6 * 5^3 * 7.
		

Crossrefs

Formula

a(n) = Product_{j=0..n} j!!!!.
a(n) = Product_{j=0..n} A007662(j).
a(n) = n!!!! * a(n-1) where a(0) = 1, a(1) = 1 and n >= 2.
a(n) = n*(n-4)!!!! * a(n-1) where a(0) = 1, a(1) = 1, a(2) = 2.

A283554 Numbers k such that k![4] - 2 is prime, where k![4] = A007662(k) = quadruple factorial.

Original entry on oeis.org

4, 5, 7, 9, 11, 15, 21, 25, 29, 49, 79, 87, 95, 125, 133, 153, 157, 185, 201, 217, 223, 289, 323, 469, 533, 567, 821, 1001, 1999, 2523, 2533, 2827, 2843, 4821, 8153, 8947, 12739, 19353, 22929, 30629, 31809, 37785, 74913, 97411
Offset: 1

Views

Author

Robert Price, Mar 10 2017

Keywords

Comments

a(45) > 10^5.
The first 9 primes associated with this sequence: 2, 3, 19, 43, 229, 3463, 208843, 5221123, 151412623.

Crossrefs

Programs

  • Mathematica
    MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
    Select[Range[2, 50000], PrimeQ[MultiFactorial[#, 4] - 2] &]

Extensions

a(43)-a(44) from Robert Price, Jul 24 2017

A288890 Primes of the form k!4+2, where k!4 is the quadruple factorial number (A007662).

Original entry on oeis.org

3, 5, 7, 23, 47, 233, 587, 3467, 65837, 40883537, 151412627, 1267389587, 74389431691577, 885821206052908127, 13005556505149168230729834377, 583723376551025432768079734666930727861956890308512536691015627
Offset: 1

Views

Author

Robert Price, Jun 18 2017

Keywords

Crossrefs

Programs

  • Mathematica
    MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
    Select[Table[MultiFactorial[i, 4] + 2, {i, 0, 100}], PrimeQ[#]&]
    Select[Table[Times@@Range[k,1,-4]+2,{k,150}],PrimeQ] (* Harvey P. Dale, Nov 24 2024 *)

A289490 Primes of the form k!4+8, where k!4 is the quadruple factorial number (A007662).

Original entry on oeis.org

11, 13, 29, 53, 239, 593, 65843, 1514213, 5221133, 4996616633, 1729986783533, 7579867420133, 36453104912477522894633, 2442358029135994033939883, 173407420068655576409731133, 534602198949923693866675351078133, 7419136758370889359733910587728133
Offset: 1

Views

Author

Robert Price, Sep 02 2017

Keywords

Crossrefs

Cf. A291343.

Programs

  • Mathematica
    MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
    Select[Table[MultiFactorial[i, 4] + 8, {i, 0, 100}], PrimeQ[#]&]

A289492 Primes of the form k!4+16, where k!4 is the quadruple factorial number (A007662).

Original entry on oeis.org

17, 19, 37, 61, 601, 65851, 40883551, 44358635491, 184874815141, 200200021673987500790641, 2442358029135994033939891, 13005556505149168230729834391, 85277434004263096088895523996891, 47579595706543208754134106245953141
Offset: 1

Views

Author

Robert Price, Sep 02 2017

Keywords

Crossrefs

Cf. A291344.

Programs

  • Mathematica
    MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
    Select[Table[MultiFactorial[i, 4] + 16, {i, 0, 100}], PrimeQ[#]&]

A289510 Primes of the form k!4+32, where k!4 is the quadruple factorial number (A007662).

Original entry on oeis.org

37, 53, 263, 617, 65867, 208877, 5221157, 40883567, 44358635507, 184874815157, 178311467764705307, 9807130727058790157, 200200021673987500790657, 173407420068655576409731157, 4551830726072842264843919206776501006328157
Offset: 1

Views

Author

Robert Price, Sep 02 2017

Keywords

Crossrefs

Cf. A291345.

Programs

  • Mathematica
    MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
    Select[Table[MultiFactorial[i, 4] + 32, {i, 0, 100}], PrimeQ[#]&]

A289518 Primes of the form k!4+64, where k!4 is the quadruple factorial number (A007662).

Original entry on oeis.org

67, 109, 3529, 10009, 65899, 151412689, 1267389649, 341094033905689, 9807130727058790189, 36453104912477522894689, 1008407509171875041482378189, 43350768819741354903275421016919057203189, 29366774490668885282893783501883117566129541193767295703189
Offset: 1

Views

Author

Robert Price, Sep 02 2017

Keywords

Crossrefs

Cf. A291347.

Programs

  • Mathematica
    MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
    Select[Table[MultiFactorial[i, 4] + 64, {i, 0, 100}], PrimeQ[#]&]
    Select[Table[Times@@Range[n,1,-4]+64,{n,200}],PrimeQ] (* Harvey P. Dale, May 31 2020 *)

A289519 Primes of the form k!4+128, where k!4 is the quadruple factorial number (A007662).

Original entry on oeis.org

131, 149, 173, 359, 3593, 65963, 151412753, 184874815253, 675141445011750931735785863483259503, 13075173582607657311300240428800205506303238072109503, 12956907789303111531153065870401861366351857094178052776930473828253
Offset: 1

Views

Author

Robert Price, Sep 02 2017

Keywords

Crossrefs

Cf. A291348.

Programs

  • Mathematica
    MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
    Select[Table[MultiFactorial[i, 4] + 128, {i, 0, 100}], PrimeQ[#]&]
    Select[Table[Times@@Range[n,1,-4]+128,{n,200}],PrimeQ] (* Harvey P. Dale, Aug 13 2023 *)

A289560 Primes of the form k!4+256, where k!4 is the quadruple factorial number (A007662).

Original entry on oeis.org

257, 277, 487, 1267389841, 50491808745015763381, 1008407509171875041482378381, 429215532868726286171043772444743140881, 4551830726072842264843919206776501006328381
Offset: 1

Views

Author

Robert Price, Sep 02 2017

Keywords

Crossrefs

Cf. A291349.

Programs

  • Mathematica
    MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
    Select[Table[MultiFactorial[i, 4] + 256, {i, 0, 100}], PrimeQ[#]&]
    Select[Table[256+Times@@Range[n,1,-4],{n,200}],PrimeQ] (* Harvey P. Dale, Nov 04 2024 *)
Showing 1-10 of 63 results. Next