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A181174
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The "Row2" sums of the powers-of-2 triangle A000079
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3
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1, 2, 24, 320, 11264, 688128, 90177536, 22817013760, 11751030521856, 11997870882291712, 24607668363952390144, 100719222642454151823360, 825394103341888069030641664, 13520781109074923362448234774528
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OFFSET
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0,2
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COMMENTS
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The a(n) represent the "Row2" sums, see A180662, of the powers-of-2 triangle A000079. This sequence is related to the Jacobsthal and triangular numbers.
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LINKS
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FORMULA
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a(n) = 2^(n*(n+1)/2)*(2^(n+1)+(-1)^n)/3.
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MATHEMATICA
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f[k_] := (2^k) (-1)^(k + 1)
t[n_] := Table[f[k], {k, 1, n}]
a[n_] := SymmetricPolynomial[n - 1, t[n]]
Table[a[n], {n, 1, 22}] (* A181174 signed *)
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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