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 1-4 of 4 results.

A182353 Primes of the form n*2^n - 5.

Original entry on oeis.org

3, 19, 59, 379, 4603, 1048571, 44040187, 7516192763, 6614661952700411, 13510798882111483, 477381560501272571, 16717361816799281147, 4869940435459321626619, 802726744224113772004900859
Offset: 1

Views

Author

Patrick Devlin, Apr 25 2012

Keywords

Comments

These are similar to the Woodall primes, A050918, and to sequence A182352, which are primes of the form n*2^n - 1 and of the form n*2^n - 3 respectively. However, this sequence seems to grow rather more slowly than those.

Examples

			3 = 2*2^2 - 5;  19 = 3*2^3 - 5;  59 = 4*2^4 - 5.

Links

Crossrefs

Cf. A050918, A182352.

Programs

  • Maple
    #choose N large, then S is the desired set
f:=n->n*2^n - 5:
S:={}:
for n from 0 to N do if(isprime(f(n))) then S:=S union {f(n)}: fi: od
  • Mathematica
    Select[Table[n*2^n-5,{n,2,100}],PrimeQ] (* Harvey P. Dale, Aug 06 2013 *)

A182354 Primes of the form n*2^n + 3.

Original entry on oeis.org

3, 5, 11, 67, 163, 10243, 22531, 7516192771, 43980465111043, 142788163609707759784588649053552643, 2637188343637273091841153207596203638787
Offset: 1

Views

Author

Patrick Devlin, Apr 25 2012

Keywords

Comments

These are similar to the Woodall primes, A050918, which are primes of the form n*2^n - 1.

Examples

			3 = 0*2^0 + 3; 5 = 1*2^1 + 3; 11 = 2*2^2 + 3; 67 = 4*2^4 + 3

Crossrefs

Cf. A050918, A182352, A182353.

Programs

  • Maple
    #choose N large, then S is the desired set
f:=n->n*2^n + 3:
S:={}:
for n from 0 to N do if(isprime(f(n))) then S:=S union {f(n)}: fi: od

A182375 Positive integers k such that k*2^k - 3 is prime.

Original entry on oeis.org

2, 4, 5, 14, 16, 17, 34, 38, 133, 175, 218, 284, 1036, 1441, 1550, 2893, 2933, 3770
Offset: 1

Views

Author

Patrick Devlin, Apr 26 2012

Keywords

Comments

Similar to the Woodall primes, A050918.
The next term in this sequence is unknown; if it is infinite, the next term is greater than 8000.

Examples

			5 = 2*2^2 - 3;  61 = 4*2^4 - 3;  157 = 5*2^5 - 3

Crossrefs

Cf. A050918. Values for primes are A182352.

Programs

  • Maple
    f:=n->n*2^n - 3:
S:={}:
for n from 0 to 300 do if(isprime(f(n))) then S:=S union {n}: fi: od

A182342 Primes of the form n*2^n + 5.

Original entry on oeis.org

5, 7, 13, 29, 389, 2053, 49157, 106501, 402653189, 1744830469, 2473901162501, 184717953466373, 774056185954309, 31057439705591620336669228531717, 70745044697537026438728012485623813
Offset: 1

Views

Author

Patrick Devlin, Apr 25 2012

Keywords

Comments

These are similar to the Woodall primes, A050918, which are primes of the form n*2^n - 1.

Examples

			5 = 0*2^0 + 5; 7 = 1*2^1 + 5; 13 = 2*2^2 + 5; 29 = 3*2^3 + 5; 389 = 6*2^6 + 5

Crossrefs

Cf. A050918, A182354, A182352, A182353.

Programs

  • Maple
    #choose N large, then S is the desired set
f:=n->n*2^n + 5:
S:={}:
for n from 0 to N do if(isprime(f(n))) then S:=S union {f(n)}: fi: od
Showing 1-4 of 4 results.

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

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