A337049 Numbers k such that (k + A000010(k))/2 and (k - A000010(k))/2 are prime.

10, 26, 30, 66, 70, 130, 146, 154, 190, 238, 246, 318, 370, 434, 498, 518, 598, 646, 658, 682, 690, 786, 814, 826, 842, 910, 946, 970, 1030, 1038, 1066, 1082, 1118, 1226, 1246, 1270, 1322, 1330, 1346, 1390, 1526, 1586, 1606, 1610, 1686, 1738, 1758, 1770, 1786, 1798, 1914, 2002, 2086, 2158, 2198

Offset

1,1

Comments

All terms are even and squarefree.

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

a(3) = 30 is in the sequence because A000010(30) = 8 and (30+8)/2 = 19 and (30-8)/2 = 11 are prime.

Maple

filter:= proc(n) local t; t:= numtheory:-phi(n); isprime((n+t)/2) and isprime((n-t)/2) end proc:
select(filter, [seq(i, i=6..10000, 4)]);

Crossrefs

Cf. A000010.

Sequence in context: A046961 A246826 A125035 * A067264 A043342 A023715

Adjacent sequences: A337046 A337047 A337048 * A337050 A337051 A337052

Keyword

nonn

Author

J. M. Bergot and Robert Israel, Aug 12 2020

Status

approved