#### Answer

$a_1=1$
$a_2=4$
$a_3=9$
$a_4=16$
$a_{5}=25$
$a_{6}=36$
$a_{7}=49$

#### Work Step by Step

We are given:
$a_{n}=a_{n-1}+2n-1$ and $a_1=1$
We evaluate:
$a_1=1$
$a_2=a_1+4-1=1+4-1=4$
$a_3=a_2+6-1=4+6-1=9$
$a_4=a_3+8-1=9+8-1=16$
$a_{5}=a_{4}+10-1=16+10-1=25$
$a_{6}=a_{5}+12-1=25+12-1=36$
$a_{7}=a_{6}+14-1=36+14-1=49$