A328036 Even semiprimes such that the next semiprime is also even.

4, 10, 58, 274, 382, 454, 458, 538, 614, 1082, 1234, 1318, 1478, 1618, 1718, 1874, 2062, 2374, 2554, 2846, 2902, 3574, 3722, 3998, 4174, 4258, 4474, 4946, 5098, 5414, 5422, 5498, 6334, 6598, 6658, 6686, 6718, 6778, 6914, 6922, 7054, 7346, 7534, 7642, 7702, 7754, 7838, 8038, 8098, 8422, 8434, 8674, 8818

Offset

1,1

Links

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

Example

a(3)=58 is a member because 58=2*29 is an even semiprime and the next semiprime is 62, which is also even.

Maple

sp:= select(t -> numtheory:-bigomega(t)=2, [$1..20000]):
sp[select(t -> sp[t]::even and sp[t+1]::even, [$1..nops(sp)-1])];

Mathematica

Select[Partition[Select[Range[10000], PrimeOmega[#]==2&], 2, 1], AllTrue[#, EvenQ]&][[All, 1]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 01 2020 *)

Crossrefs

Cf. A001358. Includes 2*A069142.

Sequence in context: A254078 A104363 A092190 * A222675 A328155 A209030

Adjacent sequences: A328033 A328034 A328035 * A328037 A328038 A328039

Keyword

nonn

Author

J. M. Bergot and Robert Israel, Oct 02 2019

Status

approved