A074046 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)=1 and a(3)=2.

1, 1, 2, 5, 17, 129, 2923, 428951, 1309535519, 565555596556379, 740857737860237412264699, 418997210078479016314891376985981834403, 310417325465458849274468827944195726858840449351291150876911355

Offset: 1

Author

Henry Bottomley, Aug 14 2002

Keywords

• nonn

Examples

			a(6)=17*5*2*(1/17+1/5+1/2)=129.
		

Crossrefs

Cf. A074047. In more than one sense A074046 comes between A000045 and A057438.

See also A121810 and A203761 and references therein.

Formula

a(n) tends towards a(n-1)^phi and 1.31809...^(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