A051919 Start with n, apply k->2k+1 until reach new record prime; sequence gives record primes.

3, 7, 11, 31, 79, 191, 223, 8191, 73727, 81919, 738197503, 51539607551, 3232601036663613174009984612954335460652964980182760163363015849805536730581466940964863

Offset

0,1

Links

Table of n, a(n) for n=0..12.

Example

0->1->3, new record prime 3 in 2 steps; 1->3->7, new record prime 7 in 2 steps; 2->5->11, new record prime 11 in 2 steps; 3->7->15->31, new record prime 31 in 3 steps; ...

Mathematica

f[0] = {start=0, k=3, steps=2}; f[n_] := f[n] = (k=start=f[n-1][[1]]+1; steps=0; While[!PrimeQ[k] || k <= f[n-1][[2]], k=2k+1; steps++]; {start, k, steps}); A051919 = Table[Print[f[n] // Last]; f[n], {n, 0, 12}][[All, 2]] (* Jean-François Alcover, Dec 10 2014 *)

Crossrefs

Cf. A051918, A052333.

Sequence in context: A091938 A333424 A186893 * A119175 A038913 A141178

Adjacent sequences: A051916 A051917 A051918 * A051920 A051921 A051922

Keyword

nice,nonn

Author

N. J. A. Sloane, Dec 18 1999

Extensions

More terms from Naohiro Nomoto, May 21 2001, who reports that the next term is > 10^130.

Status

approved