|
%I #6 Dec 12 2021 20:00:58
%S 1,2,3,13,7,25,44,116,55,974,1581,2111,1470,4289,10847,15000,6543,
%T 91466,62947,397907,498178,1452314,6025010,20197904,38946356,9385401,
%U 24843812,98842359,166808880,556542914,154570517
%N a(n)-th prime is smallest such that p(a(n))-1 is divisible by 2^(n-1) and quotient is odd.
%e n=1, a(1)=1, p(a(1))=p(1)=2 and p-1=1 is divisible by 2^(n-1)=2^0=1; moreover 2 is the smallest. n=10, a(10)=974, the 974th prime is 7681, p(974) - 1 = 7680 = 512.15, is divisible by 2^9 = 512 the quotient is 15 and no such a prime is below 7681. A057775(30) = 12348030977; A057776(30) = 556542914. It means 12348030977 is the 556542914th prime. A057777(30) = 12348030976; when A057777(30) is divided by 2^29, the quotient is 23 = A057778(30).
%Y Cf. A000040, A006093, A057773-A057778.
%K nonn
%O 1,2
%A _Labos Elemer_, Nov 02 2000
|
