A282687 a(n) = strictly increasing number m, such that m+n is the next prime and m-n is the previous prime.

4, 5, 26, 93, 144, 157, 300, 1839, 1922, 3099, 3240, 4189, 5544, 5967, 6506, 10815, 11760, 12871, 30612, 33267, 35002, 36411, 81486, 86653, 95676, 103263, 106060, 153219, 181332, 189097, 190440, 288615, 294596, 326403, 399318, 507253, 515004, 570291, 642320

Offset: 1

Author

Daniel Suteu, Feb 20 2017

Keywords

• nonn

Examples

			For n = 5, a(5) = 144, because the next prime after 144 is 149 and the previous prime before 144 is 139, where both have an equal distance of 5 from 144.
		

Links

• Daniel Suteu, Table of n, a(n) for n = 1..100

Crossrefs

Cf. A087378, A087711, A282690.

Programs

Mathematica

a = {}; Do[If[n == 1, k = 1, k = Max@ a + 1]; While[Nand[k - n == NextPrime[k, -1], k + n == NextPrime@ k], k++]; AppendTo[a, k], {n, 41}]; a (* Michael De Vlieger, Feb 20 2017 *)

Perl

use ntheory qw(:all);
for (my ($n, $k) = (1, 1) ; ; ++$n) {
    my $p = prev_prime($n) || next;
    my $q = next_prime($n);
    if ($n-$p == $k and $q-$n == $k) {
        printf("%s %s\n", $k++, $n);
    }
}