cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A090424 Smallest number that can be written in binary representation as concatenation of other primes in exactly n ways.

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%I A090424 #9 Jul 13 2013 12:03:10
%S A090424 2,11,23,47,175,95,189,375,191,381,763,1015,751,383,765,1023,1407,
%T A090424 2045,767,8123,1919,5999,1533,5623,4063,3067,3007,3039,1535,6013,6077,
%U A090424 8183,7935,11247,3069,12023,12143,6139,6015,6111,6127,3071,6079,6135,7679,32507
%N A090424 Smallest number that can be written in binary representation as concatenation of other primes in exactly n ways.
%C A090424 A090418(a(n)) = n and A090418(m) <> n for m < a(n).
%H A090424 Reinhard Zumkeller, <a href="/A090424/b090424.txt">Table of n, a(n) for n = 1..100</a>
%e A090424 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 A090424 (Haskell)
%o A090424 import Data.List (elemIndex)
%o A090424 import Data.Maybe (fromJust)
%o A090424 a090424 = (+ 1) . fromJust . (`elemIndex` a090418_list)
%o A090424 -- _Reinhard Zumkeller_, Aug 07 2012
%Y A090424 Cf. A004676, A007088.
%K A090424 nonn,base
%O A090424 1,1
%A A090424 _Reinhard Zumkeller_, Nov 30 2003
%E A090424 Based on corrections of A090418, data recomputed by _Reinhard Zumkeller_, Aug 07 2012