A100358 -id:A100358 - cp's OEIS frontend

A061421 Primes of the form 2^n+n+1.

Original entry on oeis.org

2, 7, 71, 110427941548649020598956093796432407239217743554726184882600387580788973

Offset: 1

Jason Earls, May 02 2001

nonn

Next term is 2^1884+1884+1, with 568 digits and is too large to include. - Emeric Deutsch, May 13 2006

The Wikipedia article "Zeisel number" gives a historical connection to A051015. - Jonathan Sondow, Oct 17 2017

K. S. Brown, The Sum of the Prime Factors of N (Part 2: Primes of the Form 2k-1 + k), Math Pages
Wikipedia, Zeisel number

Cf. A001580, A069539, A052007, A048744, A100357, A100358, A100359.

Cf. A061422.

a:=proc(n) if isprime(2^n+n+1)=true then 2^n+n+1 else fi end: seq(a(n),n=0..1000); # Emeric Deutsch, May 13 2006

{ta={{0}}, tb={{0}}};Do[g=n;s=2^n+n+1; If[PrimeQ[s], Print[n];ta=Append[ta, n]; tb=Append[tb, s]], {n, 1, 10000}];{ta, tb, g} (* Labos Elemer, Nov 19 2004 *)

Edited by N. J. A. Sloane, May 04 2007

A100359 Numbers k such that 2^k + k + 1 is prime.

Original entry on oeis.org

0, 2, 6, 236, 1884, 51380, 75764

Offset: 1

Labos Elemer, Nov 19 2004

a(8) > 500000. - Robert Price, May 24 2014

Cf. A001580, A061422, A069539, A052007, A048744, A100357, A100358.

{ta={{0}}, tb={{0}}};Do[g=n;s=2^n+n+1; If[PrimeQ[s], Print[n];ta=Append[ta, n]; tb=Append[tb, s]], {n, 1, 10000}];{ta, tb, g}

is(n)=ispseudoprime(2^n+n+1) \\ Charles R Greathouse IV, Feb 20 2017

a(n) = A061422(n) - 1.

a(6) from A061422 Max Alekseyev, Feb 08 2009

a(7) from Giovanni Resta, Mar 19 2014

cp's OEIS Frontend

A061421 Primes of the form 2^n+n+1.

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