

A051919


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


4



3, 7, 11, 31, 79, 191, 223, 8191, 73727, 81919, 738197503, 51539607551, 3232601036663613174009984612954335460652964980182760163363015849805536730581466940964863
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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[n1][[1]]+1; steps=0; While[!PrimeQ[k]  k <= f[n1][[2]], k=2k+1; steps++]; {start, k, steps}); A051919 = Table[Print[f[n] // Last]; f[n], {n, 0, 12}][[All, 2]] (* JeanFrançois Alcover, Dec 10 2014 *)


CROSSREFS

Cf. A051918, A052333.
Sequence in context: A131588 A091938 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



