A090424 - OEIS

%I #9 Jul 13 2013 12:03:10

%S 2,11,23,47,175,95,189,375,191,381,763,1015,751,383,765,1023,1407,

%T 2045,767,8123,1919,5999,1533,5623,4063,3067,3007,3039,1535,6013,6077,

%U 8183,7935,11247,3069,12023,12143,6139,6015,6111,6127,3071,6079,6135,7679,32507

%N Smallest number that can be written in binary representation as concatenation of other primes in exactly n ways.

%C A090418(a(n)) = n and A090418(m) <> n for m < a(n).

%H Reinhard Zumkeller, <a href="/A090424/b090424.txt">Table of n, a(n) for n = 1..100</a>

%e n=6: a(6)=95 -> '1011111': '10"11111'==2"31, '10"11"111'==2"3"7, '10"111"11'==2"7"3, '101"11"11'==5"3"3, '1011"111'==11"7 and '10111"11'==23"3, therefore A090418(95)=6.

%o (Haskell)

%o import Data.List (elemIndex)

%o import Data.Maybe (fromJust)

%o a090424 = (+ 1) . fromJust . (`elemIndex` a090418_list)

%o -- _Reinhard Zumkeller_, Aug 07 2012

%Y Cf. A004676, A007088.

%K nonn,base

%O 1,1

%A _Reinhard Zumkeller_, Nov 30 2003

%E Based on corrections of A090418, data recomputed by _Reinhard Zumkeller_, Aug 07 2012