A139056
Numbers k for which (k!-3)/3 is prime.
Original entry on oeis.org
4, 6, 12, 16, 29, 34, 43, 111, 137, 181, 528, 2685, 39477, 43697
Offset: 1
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a = {}; Do[If[PrimeQ[(-3 + n!)/3], AppendTo[a, n]], {n, 1, 1000}]; a
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for(n=1,1000,if(floor(n!/3-1)==n!/3-1,if(ispseudoprime(n!/3-1),print(n)))) \\ Derek Orr, Mar 28 2014
Definition corrected by
Derek Orr, Mar 28 2014
A076680
Numbers k such that 4*k! + 1 is prime.
Original entry on oeis.org
0, 1, 4, 7, 8, 9, 13, 16, 28, 54, 86, 129, 190, 351, 466, 697, 938, 1510, 2748, 2878, 3396, 4057, 4384, 5534, 7069, 10364
Offset: 1
Phillip L. Poplin (plpoplin(AT)bellsouth.net), Oct 25 2002
k = 7 is a term because 4*7! + 1 = 20161 is prime.
Corrected (added missed terms 2748, 2878) by
Serge Batalov, Feb 24 2015
A076134
Numbers k such that 3*k! - 1 is prime.
Original entry on oeis.org
0, 1, 2, 3, 4, 5, 9, 12, 17, 26, 76, 379, 438, 1695, 6709, 13313, 18504, 19021, 24488, 45552, 49085, 65451
Offset: 1
Phillip L. Poplin (plpoplin(AT)bellsouth.net), Oct 30 2002
k = 5 is here because 3*5! - 1 = 359 is prime.
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for n from 0 to 1000 do if isprime(3*n! - 1) then print(n) end if end do;
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Select[Range[0, 10^3], PrimeQ[3 #! - 1] &] (* Robert Price, May 27 2019 *)
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isok(n) = isprime(3*n! - 1); \\ Michel Marcus, Nov 13 2016
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ABC2 3*$a!+1
a: from 1 to 1000 // Jinyuan Wang, Feb 04 2020
A099350
Numbers k such that 4*k! - 1 is prime.
Original entry on oeis.org
0, 1, 2, 3, 5, 6, 10, 11, 51, 63, 197, 313, 579, 1264, 2276, 2669, 4316, 4382, 4678, 7907, 10843
Offset: 1
k = 5 is here because 4*5! - 1 = 479 is prime.
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for n from 0 to 1000 do if isprime(4*n! - 1) then print(n) end if end do;
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For[n = 0, True, n++, If[PrimeQ[4 n! - 1], Print[n]]] (* Jean-François Alcover, Sep 23 2015 *)
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is_A099350(n)=ispseudoprime(n!*4-1) \\ M. F. Hasler, Sep 20 2015
A099351
Numbers k such that 5*k! - 1 is prime.
Original entry on oeis.org
3, 5, 8, 13, 20, 25, 51, 97, 101, 241, 266, 521, 1279, 1750, 2204, 2473, 4193, 5181, 10080
Offset: 1
k = 5 is here because 5*5! - 1 = 599 is prime.
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for n from 0 to 1000 do if isprime(5*n! - 1) then print(n) end if end do;
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Select[Range[550],PrimeQ[5#!-1]&] (* Harvey P. Dale, Nov 27 2013 *)
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is(n)=ispseudoprime(5*n!-1) \\ Charles R Greathouse IV, Jun 13 2017
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from sympy import isprime
from math import factorial
print([k for k in range(300) if isprime(5*factorial(k) - 1)]) # Michael S. Branicky, Mar 05 2021
A180627
Numbers k such that 6*k! - 1 is prime.
Original entry on oeis.org
0, 1, 2, 5, 8, 42, 318, 326, 1054, 2987, 11243
Offset: 1
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fQ[n_] := PrimeQ[6 n! - 1]; k = 0; lst = {}; While[k < 1501, If[ fQ@k, AppendTo[lst, k]; Print@k]; k++ ]; lst
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is(k) = ispseudoprime(6*k!-1); \\ Jinyuan Wang, Feb 04 2020
A180631
Numbers k such that 10*k! - 1 is prime.
Original entry on oeis.org
2, 3, 4, 33, 55, 95, 110, 148, 170, 612, 1155, 2295, 2473, 4143, 5671
Offset: 1
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fQ[n_] := PrimeQ[10 n! - 1]; k = 0; lst = {}; While[k < 1501, If[ fQ@k, AppendTo[lst, k]; Print@k]; k++ ]; lst
A180628
Numbers k such that 7*k! - 1 is prime.
Original entry on oeis.org
2, 3, 4, 5, 6, 7, 8, 12, 23, 25, 31, 57, 74, 86, 140, 240, 310, 703, 713, 796, 1028, 1102, 1924, 3469, 3990
Offset: 1
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fQ[n_] := PrimeQ[7 n! - 1]; k = 0; lst = {}; While[k < 1501, If[ fQ@k, AppendTo[lst, k]; Print@k]; k++ ]; lst
Select[Range[4000],PrimeQ[7#!-1]&] (* Harvey P. Dale, Apr 22 2024 *)
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is(k) = ispseudoprime(7*k!-1); \\ Jinyuan Wang, Feb 03 2020
A180630
Numbers k such that 9*k! - 1 is prime.
Original entry on oeis.org
2, 3, 12, 15, 16, 25, 30, 38, 59, 82, 114, 168, 172, 175, 213, 229, 251, 302, 311, 554, 2538, 3050, 3363, 12316
Offset: 1
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fQ[n_] := PrimeQ[9 n! - 1]; k = 0; lst = {}; While[k < 1501, If[ fQ@k, AppendTo[lst, k]; Print@k]; k++ ]; lst
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is(k) = ispseudoprime(9*k!-1); \\ Jinyuan Wang, Feb 03 2020
A180629
Numbers k such that 8*k! - 1 is prime.
Original entry on oeis.org
0, 1, 3, 4, 8, 33, 121, 177, 190, 276, 473, 484, 924, 937, 1722, 2626, 4077, 4464, 6166
Offset: 1
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fQ[n_] := PrimeQ[8 n! - 1]; k = 0; lst = {}; While[k < 1501, If[ fQ@k, AppendTo[lst, k]; Print@k]; k++ ]; lst
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is(k) = ispseudoprime(8*k!-1); \\ Jinyuan Wang, Feb 03 2020
Showing 1-10 of 11 results.
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