%I #11 Jan 28 2021 21:27:45

%S 1,9,2,6,8,6,6,4,6,8,0,7,1,6,0,9,3,7,9,6,5,8,7,1,8,0,1,8,1,3,7,7,7,2,

%T 5,5,0,4,5,7,1,8,5,5,7,9,6,6,9,0,6,0,1,5,9,9,9,1,3,9,2,9,9,0,1,8,8,4,

%U 2,4,4,3,0,3,9,2,8,9,9,9,9,3,8,4,6,7,1,3,5,6,2,6,4,8,5,1,8,4,7,0,8,1,1,9,8

%N Decimal expansion of the sum of the reciprocals of the squares of composite numbers.

%C This constant is A275647 (which gives the sum of the reciprocals of the squares of nonprime numbers) minus 1.

%F Equals Sum_{k>=1} 1/A002808(k)^2.

%e Equals 1/4^2 + 1/6^2 + 1/8^2 + 1/9^2 + 1/10^2 + ... = 0.19268664680716093796587180181377725504571855796690...

%Y Cf. A275647.

%K nonn,cons

%O 0,2

%A _Jon E. Schoenfield_, Jan 26 2021