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%I #16 Nov 04 2018 03:45:06
%S 1,6,55,556,7839,118141,2488800,54871741,1374282325,35786212191,
%T 1182319284628,40234641889543,1409394785418633,53597236487797597,
%U 2091701617809524916,96271871655725943733,4719413412748380767833
%N Duplicate of A118836.
%C Previous name was: Denominator of fraction equal to the continued fraction [4, 6, 9, ..., semiprime(n)].
%C Numerator of fraction equal to the continued fraction [4, 6, 9, ..., semiprime(n)] is A121660. Hence A121660/A121661 is semiprime analog of A036247/A036248.
%F a(n) = A118836(n). - _Georg Fischer_, Nov 02 2018
%e a(1) = denominator of 4 = 1.
%e a(2) = denominator of 4 + 1/6 = denominator of 25/6 = 6.
%e a(3) = denominator of 4 + 1/(6+1/9) = denominator of 229/55 = 55.
%e a(10) = denominator of 4+1/(6+1/(9+1/(10+ 1/(14+1/(15+ 1/(21+1/(22+1/(25+1/(26))))))))) = denominator of 149001936472/35786212191 = 35786212191.
%p A121661 := proc(n) local x,i ; x := A001358(n) ; for i from n-1 to 1 by -1 do x := A001358(i)+1/x ; end do: denom(%) ; end proc: # _R. J. Mathar_, Jun 29 2011
%K dead
%O 1,2
%A _Jonathan Vos Post_, Aug 14 2006
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