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 A141288 a(0)=1. a(n) = smallest positive multiple of a(n-1) such that a(n) contains the binary representation of n at least once somewhere within its binary representation. 1

%I

%S 1,1,2,6,12,84,252,252,504,2520,17640,52920,52920,52920,52920,476280,

%T 952560,952560,4762800,61916400,185749200,928746000,928746000,

%U 928746000,928746000,4643730000,13931190000,13931190000,13931190000,13931190000

%N a(0)=1. a(n) = smallest positive multiple of a(n-1) such that a(n) contains the binary representation of n at least once somewhere within its binary representation.

%e 6 in binary is 110. Checking the multiples of a(5)=84: 1*84 = 84 = 1010100 in binary. 110 does not occur. 2*84 = 168 = 10101000 in binary. 110 does not occur. But 3*84 = 252 = 11111100 in binary. 110 occurs in this like so: 1111(110)0. So a(6) = 252.

%p contai := proc(a,n) verify(convert(n,base,2), convert(a,base,2),sublist) ; end: A141288 := proc(n) option remember; local k ; if n= 0 then 1; else for k from 1 do if contai(k*procname(n-1),n) then RETURN( k*procname(n-1) ) ; fi; od: fi; end: seq(A141288(n),n=0..40) ; # _R. J. Mathar_, Feb 19 2009

%K base,nonn

%O 0,3

%A _Leroy Quet_, Aug 01 2008

%E Extended by _R. J. Mathar_, Feb 19 2009

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Last modified April 22 08:06 EDT 2019. Contains 322329 sequences. (Running on oeis4.)