A096450 Primes p such that the number of primes q, 7 <= q < p, congruent to 1 or 2 mod 5, is equal to the number of such primes congruent to 3 or 4 mod 5.

7, 29, 37, 61, 89, 101, 107, 113, 131, 151, 181, 239, 251, 271, 397, 421, 443, 463, 479, 491, 503, 557, 569, 577, 601, 743, 757, 787, 857, 863, 881, 887, 1291, 1511, 1531, 1549, 1609, 1657, 1667, 1693, 1699, 1861, 1987, 1997, 2003, 2017, 2053, 2377, 2393

Offset: 1

Author

Yasutoshi Kohmoto, Aug 12 2004

Keywords

• nonn
• easy

Comments

First term prime(4) = 7 is placed on 0th row.

If prime(n-1) = 1 or 2 mod 5 is on k-th row then we put prime(n) on (k-1)-st row.

If prime(n-1) = -1 or -2 mod 5 is on k-th row then we put prime(n) on (k+1)-st row.

This process produces the following array of prime numbers:

31, 97, ... row -1

7, 29, 37, 61, 89, 101, ... row 0 (this sequence)

11, 17, 23, 41, 47, 59, 67, 83, ... row 1 (A096454)

13, 19, 43, 53, 71, 79, ... row 2 (A096455)

73, ...

Crossrefs

Cf. A096448-A096455.

Extensions

More terms and better definition from Joshua Zucker, May 21 2006