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A208241 Smallest prime greater than n, with n as prefix in binary representation. 5
2, 5, 7, 17, 11, 13, 29, 17, 19, 41, 23, 97, 53, 29, 31, 67, 71, 37, 79, 41, 43, 89, 47, 97, 101, 53, 109, 113, 59, 61, 127, 131, 67, 137, 71, 73, 149, 307, 79, 163, 83, 337, 173, 89, 181, 373, 191, 97, 197, 101, 103, 211, 107, 109, 223, 113, 229, 233, 239 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A208238(n) <= a(n);

A174332(n) = a(A000040(n)).

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

MAPLE

A208241 := proc(n)

    local nbin, len, suf, sufbin, pbin, p ;

    nbin := convert(n, base, 2) ;

    for len from 1 do

        for suf from 0 to 2^len-1 do

            sufbin := convert(suf, base, 2) ;

            while nops(sufbin) < len do

                sufbin := [op(sufbin), 0] ;

            end do:

            pbin := [op(sufbin), op(nbin)] ;

            p := add( 2^(i-1)*op(i, pbin), i=1..nops(pbin) ) ;

            if isprime(p) then

                return p ;

            end if;

        end do:

    end do:

end proc:

seq(A208241(n), n=1..50) ; # R. J. Mathar, May 06 2017

PROG

(Haskell)

import Data.List (genericIndex, find, isPrefixOf)

import Data.Maybe (fromJust)

a208241 = genericIndex a208241_list

a208241_list = f nns $ filter ((== 1) . a010051' . fst) nns where

   f mms'@((m, ms):mms) pps'@((p, ps):pps) =

     if m == p then f mms' pps else q : f mms pps'

     where q = fst $ fromJust $ find ((ms `isPrefixOf`) . snd) pps'

   nns = zip [1..] $ map reverse $ tail a030308_tabf

CROSSREFS

Cf. A208238, A004676, A007088, A010051, A030308, A055011.

Sequence in context: A181447 A082088 A075881 * A089727 A113514 A145674

Adjacent sequences:  A208238 A208239 A208240 * A208242 A208243 A208244

KEYWORD

nonn,base

AUTHOR

Reinhard Zumkeller, Feb 14 2013

STATUS

approved

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Last modified September 21 17:46 EDT 2019. Contains 327273 sequences. (Running on oeis4.)