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A088534
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Number of representations of n by the quadratic form x^2+xy+y^2 with 0<=x<=y.
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11
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1, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 2, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 2, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,50
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COMMENTS
| a(A118886(n)) > 1; A198772(a(n)) = 1; A198773(a(n)) = 2; A198774(a(n)) = 3; A198775(a(n)) = 4; a(A198799(n)) = n and a(m) <> n for m < A198799(n). [Reinhard Zumkeller, Oct 30 2011]
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REFERENCES
| B. C. Berndt,"On a certain theta-function in a letter of Ramanujan from Fitzroy House", Ganita 43 (1992),33-43
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LINKS
| Reinhard Zumkeller, Table of n, a(n) for n = 0..10000
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FORMULA
| a(A003136(n))>0; a(A034020(n))=0
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PROG
| (PARI) a(n)=sum(i=0, n, sum(j=0, i, if(i^2+i*j+j^2-n, 0, 1)))
(Haskell)
a088534 n = length
[(x, y) | y <- [0..a000196 n], x <- [0..y], x^2 + x*y + y^2 == n]
a088534_list = map a088534 [0..]
-- Reinhard Zumkeller, Oct 30 2011
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CROSSREFS
| Cf. A003136, A034020.
Cf. A000196.
Sequence in context: A025444 A092575 A065335 * A178602 A025441 A176891
Adjacent sequences: A088531 A088532 A088533 * A088535 A088536 A088537
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KEYWORD
| nonn
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AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Nov 16 2003
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