Complete the sequence

1, 13, 2, 1, 5, 3, 2, 1, 4, 4, 7, 3, 1, 5, 3, 5, ___, ___

Eight queens problem

Place 8 queens in 8X8 chessboard such that none of them able to
capture any other by standard moves of queen. That is no 2 queens
would be able to attack each other.
[also try general queens problem of placing n queens in nxn chessboard]

Find the length of the bridge ?

There is a river which is 4100 inches wide, and the bridge across the
river is in such a way that one seventh of the overall length of the
bridge was on one side of the river and one eighth of the bridge was
on the other side of the river.
Find the total length of the bridge?

[Note: The bridge perfectly straight]

Chess board problem

what is maximum no. of kings which can be placed on a chessboard so
that no 2 of them put each other in check?
[provided all kings are of one color and check rule is applicable to
same color kings]