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A119906 Largest number whose factorial is less than 10^(10^n). 1
3, 13, 69, 449, 3248, 25205, 205022, 1723507, 14842906, 130202808, 1158787577, 10433891463, 94851898540, 869200494599, 8019346203785, 74419210652835, 694100859679691, 6502464891216879, 61154108320430275, 577134533044522749 (list; graph; refs; listen; history; internal format)
OFFSET

0,1

EXAMPLE

a(1) = 13 because 10^(10^1) = 10^10 = 10000000000 and 13! = 6227020800 is largest factorial less than this.

MAPLE

A119906Stirling := proc(n) local i; fsolve( (i+0.5)*log(i+1.0)=log(10.0)*10.0^n+i-1.0-0.5*log(2.0*Pi)-1./12.0/i, i) ; end : A119906 := proc(n::integer) local aestim::integer, resul::integer, faci1::integer, faci::integer, pow10::integer, i ; pow10 := 10^(10^n) ; aestim := floor(A119906Stirling(n))-1 ; faci1 := factorial(aestim) ; for i from aestim+1 to aestim+9 do faci := factorial(i) ; if faci1< pow10 and faci >= pow10 then RETURN(i-1) ; fi ; faci1 := faci ; end ; RETURN(0) ; end: for n from 0 to 30 do printf("%d, ", A119906(n)) ; od ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 04 2006

CROSSREFS

Cf. A000142, A061010.

Sequence in context: A184818 A007808 A104989 * A059726 A192209 A154677

Adjacent sequences:  A119903 A119904 A119905 * A119907 A119908 A119909

KEYWORD

nonn

AUTHOR

Julien Peter Benney (jpbenney(AT)ftml.net), Aug 01 2006

EXTENSIONS

a(6) from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 04 2006

More terms from Jon E. Schoenfield (jonscho(AT)hiwaay.net), Aug 09 2006

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Last modified February 14 02:38 EST 2012. Contains 205567 sequences.