A178502 Numbers n such that prime(n) modulo n is less than n/2.

1, 5, 6, 7, 8, 12, 13, 14, 15, 16, 17, 18, 21, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 69, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108

Offset

1,2

Comments

The sequence consists largely of long runs of consecutive integers. However, there are also a few isolated integers such that the distance to both neighbor terms is greater than 1: 21, 69, 181, 1052, 4137, 4142, 6466, 63424, 100362.

Links

Table of n, a(n) for n=1..67.

Example

1 is a term because prime(1) mod 1 = 2 mod 1 = 0 < 1/2; 5 is a term because prime(5) mod 5 = 11 mod 5 = 1 < 5/2; 6 is a term because prime(6) mod 6 = 13 mod 6 = 1 < 6/2.

Prog

(PARI) for(n=1, 300, prime(n)%n<n/2&print1(n", "))
(Magma) [ n: n in [1..120] | NthPrime(n) mod n lt n/2 ];

Crossrefs

Cf. companion sequence A178462.

Sequence in context: A339746 A262513 A130206 * A047322 A236242 A309102

Adjacent sequences: A178499 A178500 A178501 * A178503 A178504 A178505

Keyword

nonn

Author

Zak Seidov, Dec 23 2010

Status

approved