A057776 a(n)-th prime is smallest such that p(a(n))-1 is divisible by 2^(n-1) and quotient is odd.

1, 2, 3, 13, 7, 25, 44, 116, 55, 974, 1581, 2111, 1470, 4289, 10847, 15000, 6543, 91466, 62947, 397907, 498178, 1452314, 6025010, 20197904, 38946356, 9385401, 24843812, 98842359, 166808880, 556542914, 154570517

Offset

1,2

Links

Table of n, a(n) for n=1..31.

Example

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).

Crossrefs

Cf. A000040, A006093, A057773-A057778.

Sequence in context: A087564 A306431 A192362 * A110362 A074478 A046421

Adjacent sequences: A057773 A057774 A057775 * A057777 A057778 A057779

Keyword

nonn

Author

Labos Elemer, Nov 02 2000

Status

approved