%I #4 Feb 11 2024 22:58:44
%S 6,2,8,4,0,7,3,9,5,1,7,4,0,6,2,8,5,1,7,3,9,5,2,8,4,0,6,3,9,5,1,7,3,0,
%T 6,2,8,4,1,7,3,9,5,1,8,4,0,6,2,9,5,1,7,3,9
%N a(n) = first digit to the right of decimal point of n*(sqrt(5)-1)/2.
%D J. Kappraff, Beyond Measure, World Scientific, 2002, p. 537.
%F n*0.618033989..., discard integer, then extract first digit to right of decimal.
%e 12th term is 4 since (12)(.618033989...) = 7.4164...
%o (PARI) a(n)=(sqrtint(125*n^2)-n%2*5)%10 \\ _Charles R Greathouse IV_, Feb 11 2024
%K nonn,base,easy
%O 1,1
%A _Gary W. Adamson_, May 07 2003