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A088560
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Sum of odd entries in row n of Pascal's triangle.
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3
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1, 2, 2, 8, 2, 12, 32, 128, 2, 20, 92, 464, 992, 4032, 8192, 32768, 2, 36, 308, 2320, 9692, 52712, 164320, 781312, 1470944, 6249152, 13748672, 56768768, 67100672, 268419072, 536870912, 2147483648, 2, 68, 1124, 14352, 117812, 1003960, 5670400
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OFFSET
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0,2
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COMMENTS
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a(n) = a power of 2 iff n = 2^k - 2, 2^k - 1 or 2^k.
a(n) = A088504(n) iff n = 2^k - 2, k>1. a(n) > A088504(n) iff n = 2^k - 1.
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LINKS
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FORMULA
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a(2^n)=2; a(2^n-1)=2^(2^n-1); a(2^n+1)=2^(n+1)+4 ... - Benoit Cloitre, Nov 19 2003
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MAPLE
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T:= [1]: R:= 1:
for i from 1 to 50 do
T:= [1, op(T[2..-1]+T[1..-2]), 1];
R:= R, convert(select(type, T, odd), `+`)
od:
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MATHEMATICA
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f[n_] := Plus @@ Select[ Table[ Binomial[n, i], {i, 0, n}], OddQ[ # ] & ]; Table[ f[n], {n, 0, 38}] (* Robert G. Wilson v, Nov 19 2003 *)
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PROG
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(PARI) a(n)=sum(i=0, n, binomial(n, i)*(binomial(n, i)%2))
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CROSSREFS
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KEYWORD
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AUTHOR
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Yuval Dekel (dekelyuval(AT)hotmail.com), Nov 17 2003
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EXTENSIONS
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STATUS
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approved
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