

A328036


Even semiprimes such that the next semiprime is also even.


1



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
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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



