A090424 - OEIS

A090424

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

2, 11, 23, 47, 175, 95, 189, 375, 191, 381, 763, 1015, 751, 383, 765, 1023, 1407, 2045, 767, 8123, 1919, 5999, 1533, 5623, 4063, 3067, 3007, 3039, 1535, 6013, 6077, 8183, 7935, 11247, 3069, 12023, 12143, 6139, 6015, 6111, 6127, 3071, 6079, 6135, 7679, 32507

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

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

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..100

EXAMPLE

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.

PROG

(Haskell)

import Data.List (elemIndex)

import Data.Maybe (fromJust)

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

-- Reinhard Zumkeller, Aug 07 2012

CROSSREFS

Cf. A004676, A007088.

Sequence in context: A294551 A179878 A126916 * A056637 A141423 A344032

Adjacent sequences: A090421 A090422 A090423 * A090425 A090426 A090427

KEYWORD

nonn,base

AUTHOR

Reinhard Zumkeller, Nov 30 2003

EXTENSIONS

Based on corrections of A090418, data recomputed by Reinhard Zumkeller, Aug 07 2012

STATUS

approved