A175490 - OEIS

%I #14 Feb 05 2020 15:00:47

%S 1,2,3,8,20,144,63,256,1152,1600,118800,995328,8424000,12192768,

%T 178605,1048576,8912896,21233664,27572576256,13107200000,537600000,

%U 2032335360000,30928035600000,760840571584512,13541327555788800

%N a(n) = Product_{k=1..n} b(k,n), where b(k,n) is the largest positive integer that, when written in binary, occurs as a substring in both binary k and binary n.

%C Row products of A175488. - _R. J. Mathar_, Sep 28 2010

%H Rémy Sigrist, <a href="/A175490/b175490.txt">Table of n, a(n) for n = 1..819</a>

%H Rémy Sigrist, <a href="/A175490/a175490.gp.txt">PARI program for A175490</a>

%p A175488 := proc(n,m) for a from m to 1 by -1 do abin := convert(a,base,2) ; nbin := convert(n,base,2) ; mbin := convert(m,base,2) ; if verify(abin,nbin,'sublist') and verify(abin,mbin,'sublist') then return a; end if; end do: end proc:

%p A175490 := proc(n) mul(A175488(n,m),m=1..n) ; end proc:

%p seq(A175490(n),n=1..30) ;

%p # _R. J. Mathar_, Sep 28 2010

%o (PARI) See Links section.

%Y Cf. A175488, A175489.

%K base,nonn

%O 1,2

%A _Leroy Quet_, May 28 2010

%E More terms from _R. J. Mathar_, Sep 28 2010