How to select only the line that after pattern?

[papori]

Hi all,
Assuming i have this text:
@HISEQ1:1360NU8ACXX:5:1101:4153:1981 1:N:0:ACTTGA
ATTGCAATACTAACTGTGACTCAACTGAGGAGTTAAGATGTANNNNNNNN
+
CCCFFFFFHHHHHJJJJJJJJJJIJIA<CCC2111:EGH?1?:?DHHIGI
@HISEQ1:1360NU8ACXX:5:1101:4876:1982 1:N:0:ACTTGA
ATCATCCTTCTTCATTTCTGGGGGTTTGTCTGGTTTCAGAGGAGCTGCTT
+
CCCFFFFFHHHHHIJJJJJJJJ@<1??GHII:002?DHGGHFHIIIIHHI
@HISEQ1:1360NU8ACXX:5:1101:4876:1982 1:N:0:ACTTGA
ATCATCCTTCTTCATTTCTGGGGGTTTGTCTGGTTTCAGAGGAGCTGCTT
+
CCCFFFFFHHHHHIJJJJJJJJ@<1??GHII:002?DHGGHFHIIIIHHI
@HISEQ1:1360NU8ACXX:5:1101:4876:1982 1:N:0:ACTTGA
ATCATCCTTCTTCATTTCTGGGGGTTTGTCTGGTTTCAGAGGAGCTGCTT
+
CCCFFFFFHHHHHIJJJJJJJJ@<1??GHII:002?DHGGHFHIIIIHHI

i want to select only the first line after "@HISEQ" in all the file.
in this example the output should be :
ATTGCAATACTAACTGTGACTCAACTGAGGAGTTAAGATGTANNNNNNNN
ATCATCCTTCTTCATTTCTGGGGGTTTGTCTGGTTTCAGAGGAGCTGCTT
ATCATCCTTCTTCATTTCTGGGGGTTTGTCTGGTTTCAGAGGAGCTGCTT
ATCATCCTTCTTCATTTCTGGGGGTTTGTCTGGTTTCAGAGGAGCTGCTT

How can i do this?
I found grep -A1, but it select also the @HISEQ line...

Thanks,
Pap