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 12 results. Next

A076185 Numbers n such that n!! + 2 is prime.

Original entry on oeis.org

0, 1, 3, 5, 7, 9, 21, 23, 27, 57, 75, 103, 169, 219, 245, 461, 695, 1169, 3597, 3637, 7495, 27743, 28799, 32501
Offset: 1

Views

Author

Zak Seidov, Nov 02 2002

Keywords

Comments

a(25) > 50000. - Robert Price, Jan 18 2015
a(1)=0 since 0!!=1 and 1+2 = 3 is prime. - Robert Price, Jan 18 2015

Links

Crossrefs

Cf. A006882, A080778 and A076186, A076188, A076189, A076190, A076193, A076194, A076195, A076196, A076197 for other values of s in n!! + 2^s.

Programs

Extensions

Edited and extended (n<4096) by Hugo Pfoertner, Jun 19 2003
One more term from Herman Jamke (hermanjamke(AT)fastmail.fm), Dec 30 2007
a(22) - a(23) from Robert Price, Oct 17 2012
a(24) from Robert Price, Jan 18 2015

A076188 Numbers k such that k!! + 2^3 is prime.

Original entry on oeis.org

3, 5, 7, 9, 15, 17, 25, 41, 63, 79, 91, 103, 299, 341, 431, 445, 465, 519, 1251, 2469, 2507, 2549, 6817, 8519, 18983, 38715
Offset: 1

Views

Author

Zak Seidov, Nov 02 2002

Keywords

Comments

a(27) > 50000. - Robert Price, Jan 06 2015

Links

Crossrefs

Cf. A006882, A080778 and A076185, A076186, A076189, A076190, A076193, A076194, A076195, A076196, A076197 for other values of s in n!!+2^s.

Programs

  • Mathematica
    lst={}; Do[If[PrimeQ[n!!+2^3], AppendTo[lst, n]], {n, 0, 50000}]; lst
Select[Range[40000],PrimeQ[#!!+8]&] (* Harvey P. Dale, May 28 2021 *)

Extensions

Edited and extended (n<4096) by Hugo Pfoertner, Jun 19 2003
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008
a(25) from Robert Price, Nov 01 2012
a(26) from Robert Price, Jan 06 2015

A076186 Numbers n such that n!! + 2^2 is prime.

Original entry on oeis.org

0, 1, 3, 5, 7, 11, 17, 29, 39, 43, 73, 93, 315, 549, 2059, 5543, 6937, 22819, 34523
Offset: 1

Views

Author

Zak Seidov, Nov 02 2002

Keywords

Comments

a(20) > 50000. - Robert Price, Feb 05 2015
Since 0!! is defined to be unity (A006882), 0!! + 2^2 = 5, which is prime. - Robert Price, Mar 22 2015

Links

Crossrefs

Cf. A006882, A080778 and A076185, A076188, A076189, A076190, A076193, A076194, A076195, A076196, A076197 for other values of s in n!! + 2^s.

Programs

  • Mathematica
    Select[Range[0, 1000], PrimeQ[#!! + 4] &] (* Robert Price, Mar 22 2015 *)

Extensions

Edited and extended (n<4096) by Hugo Pfoertner, Jun 19 2003
6937 from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008
Corrected by Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008
a(18) = 22819 from Robert Price, Oct 04 2012
a(19) = 34523 from Robert Price, Feb 05 2015
a(1)=0 prepended by Robert Price, Mar 22 2015

A076189 Numbers k such that k!! + 2^4 is prime.

Original entry on oeis.org

0, 1, 3, 5, 13, 17, 25, 27, 39, 45, 47, 53, 177, 217, 401, 637, 729, 787, 843, 3407, 8835, 10283, 14061, 21951
Offset: 1

Views

Author

Zak Seidov, Nov 02 2002

Keywords

Comments

a(25) > 50000. - Robert Price, Jan 19 2015
a(1)=0 since 0!!=1 and 1 + 2^4 = 17 is prime. - Robert Price, Jan 19 2015

Links

Crossrefs

Cf. A006882, A080778 and A076185, A076186, A076188, A076190, A076193, A076194, A076195, A076196, A076197 for other values of s in n!! + 2^s.

Programs

  • Maple
    select(t -> isprime(doublefactorial(t)+16), [$0..1000]); # Robert Israel, Jan 19 2015
  • Mathematica
    lst={}; Do[If[PrimeQ[n!!+2^4], AppendTo[lst, n]], {n, 0, 50000}]; lst

Extensions

Edited and extended (n < 4096) by Hugo Pfoertner, Jun 19 2003
8835 from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008
a(22)-a(24) from Robert Price, Jan 01 2013
a(1)=0 prepended by Robert Price, Jan 19 2015

A076190 Numbers n such that n!! + 2^5 is prime.

Original entry on oeis.org

5, 7, 9, 11, 15, 21, 33, 41, 43, 45, 67, 93, 117, 327, 363
Offset: 1

Views

Author

Zak Seidov, Nov 02 2002

Keywords

Comments

a(16) > 50000. - Robert Price, Jan 02 2015

Links

Crossrefs

Cf. A006882, A080778 and A076185, A076186, A076188, A076189, A076193, A076194, A076195, A076196, A076197 for other values of s in n!! + 2^s.

Programs

  • Mathematica
    lst={}; Do[If[PrimeQ[n!!+2^5], AppendTo[lst, n]], {n, 0,50000}]; lst
Select[Range[400],PrimeQ[#!!+32]&] (* Harvey P. Dale, Jul 22 2021 *)

Extensions

Edited and checked (n<4096) by Hugo Pfoertner, Jun 19 2003

A076193 Numbers k such that k!! + 2^6 is prime.

Original entry on oeis.org

3, 5, 9, 11, 17, 19, 23, 51, 219, 421, 2845, 4691, 10617
Offset: 1

Views

Author

Zak Seidov, Nov 02 2002

Keywords

Comments

a(14) > 50000. - Robert Price, Mar 22 2015

Links

Crossrefs

Cf. A006882, A080778 and A076185, A076186, A076188, A076189, A076190, A076194, A076195, A076196, A076197 (other values of s in n!! + 2^s).

Programs

  • Mathematica
    Select[Range[0, 1000], PrimeQ[#!! + 64] &] (* Robert Price, Mar 22 2015 *)

Extensions

Edited and extended (n < 4096) by Hugo Pfoertner, Jun 19 2003
a(12)-a(13) from Robert Price, Jan 23 2013

A076194 Numbers k such that k!! + 2^7 is prime.

Original entry on oeis.org

3, 7, 17, 19, 31, 43, 51, 163, 215, 269, 297, 457, 599, 633, 795, 999, 1027, 1261, 2567, 14315, 39505, 44725
Offset: 1

Views

Author

Zak Seidov, Nov 02 2002

Keywords

Comments

a(23) > 50000. - Robert Price, Mar 09 2015

Links

Crossrefs

Cf. A006882, A080778 and A076185, A076186, A076188, A076189, A076190, A076193, A076195, A076196, A076197 for other values of s in n!! + 2^s.

Extensions

Edited and extended (n < 4096) by Hugo Pfoertner, Jun 19 2003
a(20) from Robert Price, Feb 04 2013
a(21)-a(22) from Robert Price, Mar 09 2015

A076195 Numbers k such that k!! + 2^8 is prime.

Original entry on oeis.org

0, 1, 5, 9, 11, 13, 23, 135, 187, 215, 233, 313, 333, 493, 1459, 2753, 2813, 6411, 31191, 38303, 41487
Offset: 1

Views

Author

Zak Seidov, Nov 02 2002

Keywords

Comments

a(22) > 50000. - Robert Price, Jan 14 2015
a(1)=0 since 0!!=1 and 1 + 2^8 = 257 is prime. - Robert Price, Jan 14 2015

Links

Crossrefs

Cf. A006882, A080778 and A076185, A076186, A076188, A076189, A076190, A076193, A076194, A076196, A076197 for other values of s in n!! + 2^s.

Programs

  • Mathematica
    lst={}; Do[If[PrimeQ[n!!+2^8], AppendTo[lst, n]], {n, 0, 50000}]; lst

Extensions

Edited and extended (n < 4096) by Hugo Pfoertner, Jun 19 2003
a(18) from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008
a(1)=0 prepended and a(19)-a(21) from Robert Price, Jan 14 2015

A076196 Numbers k such that k!! + 2^9 is prime.

Original entry on oeis.org

7, 13, 15, 19, 25, 133, 135, 199, 223, 297, 299, 511, 15263, 16491, 18967, 32455
Offset: 1

Views

Author

Zak Seidov, Nov 02 2002

Keywords

Comments

a(17) > 50000. - Robert Price, Feb 15 2015

Links

Crossrefs

Cf. A006882.
Numbers k such that k!! + 2^s is prime: A080778 (s=0), A076185 (s=1), A076186 (s=2), A076188 (s=3), A076189 (s=4), A076190 (s=5), A076193 (s=6), A076194 (s=7), A076195 (s=8), A076197 (s=10).

Programs

Extensions

Edited and extended (n < 4096) by Hugo Pfoertner, Jun 19 2003
a(13)-a(15) from Robert Price, Feb 25 2013
a(16) from Robert Price, Feb 15 2015

A257864 Numbers n such that n!! - 2^7 is prime.

Original entry on oeis.org

11, 13, 21, 47, 59, 77, 109, 129, 155, 163, 245, 337, 511, 1417, 3013, 3757, 4989, 8977, 12479, 12869
Offset: 1

Views

Author

Robert Price, May 11 2015

Keywords

Comments

a(21) > 50000. - Robert Price, May 11 2015
a(n) is odd. - Chai Wah Wu, May 12 2015

Links

Crossrefs

Cf. A007749, A094144, A123910 (other forms of n!!-2^k)
Cf. A080778, A076185, A076186, A076188, A076189, A076190, A076193, A076194, A076195, A076196, A076197 (other forms of n!!+2^k)

Programs

  • Mathematica
    Select[Range[0, 50000], #!! - 128 > 0 && PrimeQ[#!! - 128] &]
  • PARI
    is(n)=ispseudoprime(prod(i=0,(n-1)\2, n-2*i)-128) \\ Charles R Greathouse IV, May 11 2015
  • Perl
    use ntheory ":all"; use Math::GMPz;
sub mf2 { my($n,$P)=(shift,Math::GMPz->new(1)); $P *= $n-($_<<1) for 0..($n-1)>>1; $P; }
for (1..100000) { say if is_prob_prime(mf2($)-128) } # _Dana Jacobsen, May 13 2015
  • Python
    from gmpy2 import is_prime, mpz
A257864_list, g, h = [], mpz(105), mpz(128)
for i in range(9,10**5,2):
    g *= i
    if is_prime(g-h):
        A257864_list.append(i) # Chai Wah Wu, May 12 2015
Showing 1-10 of 12 results. Next

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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