A055011 a(n+1) = next smallest prime beginning with a(n) when written in binary, starting with 2.

2, 5, 11, 23, 47, 191, 383, 3067, 12269, 196307, 6281839, 50254717, 201018869, 804075479, 1608150959, 102921661397, 1646746582367, 13173972658937, 105391781271503, 210783562543007, 3372537000688127, 26980296005505019, 863369472176160611, 6906955777409284889

Offset

0,1

Comments

a(5)=191 because a(4)=47 which in binary is 101111, none of 1011110(94) 1011111(95) 10111100(188) 10111101(189) 10111110 (190) are prime, but 10111111(191) is.

Links

Table of n, a(n) for n=0..23.

Formula

a(n+1) = A208241(a(n)). - Reinhard Zumkeller, Feb 14 2013

Maple

A055011 := proc(n)
    option remember;
    if n = 0 then
        2 ;
    else
        A208241(procname(n-1)) ;
    end if;
end proc: # R. J. Mathar, May 06 2017

Prog

(Haskell)
a055011 n = a055011_list !! n
a055011_list = iterate a208241 2  -- Reinhard Zumkeller, Feb 14 2013

Crossrefs

Cf. A048549 for base 10 analog.

A055011, A261200 and A261201 are all essentially the same sequence.

Sequence in context: A105120 A084403 A261201 * A007505 A246492 A059411

Adjacent sequences: A055008 A055009 A055010 * A055012 A055013 A055014

Keyword

base,easy,nonn

Author

Henry Bottomley, May 31 2000

Status

approved