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A014719
Squares of elements in Pascal triangle (by row) that are not 1.
1
4, 9, 9, 16, 36, 16, 25, 100, 100, 25, 36, 225, 400, 225, 36, 49, 441, 1225, 1225, 441, 49, 64, 784, 3136, 4900, 3136, 784, 64, 81, 1296, 7056, 15876, 15876, 7056, 1296, 81, 100, 2025, 14400, 44100, 63504, 44100, 14400, 2025, 100, 121, 3025
OFFSET
2,1
COMMENTS
Number of ways to place 2k*(n-k) nonattacking ferses on a 2k X (2n-2k) board. - Tricia Muldoon Brown, Dec 12 2018
LINKS
Tricia Muldoon Brown, The Problem of Pawns, arXiv:1811.09606 [math.CO], 2018.
FORMULA
a(n) = A014410(n)^2. - Sean A. Irvine, Nov 18 2018
EXAMPLE
Triangle begins:
4,
9, 9,
16, 36, 16,
25, 100, 100, 25,
36, 225, 400, 225, 36,
...
MAPLE
T:=(n, k)->binomial(n, k)^2: seq(seq(T(n, k), k=1..n-1), n=2..11); # Muniru A Asiru, Dec 12 2018
MATHEMATICA
Select[Flatten[Table[Binomial[n, i]^2, {n, 0, 25}, {i, 0, n}]], #>1 &] (* Vincenzo Librandi, Nov 19 2018 *)
CROSSREFS
Sequence in context: A140978 A106410 A065737 * A139417 A329732 A298816
KEYWORD
nonn,tabl
EXTENSIONS
More terms from Sean A. Irvine, Nov 18 2018
Offset corrected by Joerg Arndt, Nov 19 2018
STATUS
approved