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A074047 a(n)=a(n-1)*a(n-2)*a(n-3)*(1/a(n-1)+1/a(n-2)+1/a(n-3)) starting with a(1)=a(2)=a(3)=1. 2
1, 1, 1, 3, 7, 31, 331, 12795, 4642051, 60935796571, 283646808320375611, 17285560913056915909539455163, 4902995236325455290013100337511909917402705547 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Using the simplified formula which extends the original one to terms that may be zero, one could prefix the values (1, 1, 0), cf. A121810. See also A203761 and references therein. - M. F. Hasler, Jan 01 2013

LINKS

Table of n, a(n) for n=1..13.

FORMULA

a(n) tends towards a(n-1)^phi and 1.22376...^(phi^n) where phi=(1+sqrt(5))/2=1.6180339887...

a(n)=a(n-1)*a(n-2)+a(n-3)*a(n-1)+a(n-2)*a(n-3). - M. F. Hasler, Jan 01 2013

EXAMPLE

a(7)=31*7*3*(1/31+1/7+1/3)=331.

CROSSREFS

Cf. A074046.

Sequence in context: A063896 A156895 * A121810 A081475 A123212 A213437

Adjacent sequences:  A074044 A074045 A074046 * A074048 A074049 A074050

KEYWORD

nonn

AUTHOR

Henry Bottomley, Aug 14 2002

STATUS

approved

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Last modified May 18 07:10 EDT 2013. Contains 225419 sequences.