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A088910
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Conjectured minimal required number k of terms in a representation n=sum_(i=1..k)e_i*(p_i)^2 by distinct primes p_i, where e_i is 1 or -1.
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3
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4, 3, 4, 4, 1, 2, 5, 5, 4, 1, 4, 4, 3, 2, 4, 3, 2, 5, 5, 4, 3, 2, 4, 3, 2, 1, 4, 4, 3, 2, 3, 5, 4, 3, 2, 4, 3, 4, 3, 3, 2, 5, 5, 4, 3, 2, 4, 3, 2, 1, 4, 4, 3, 2, 3, 5, 4, 3, 2, 4, 5, 4, 3, 3, 4, 3, 5, 4, 3, 4, 3, 3, 2, 3, 2, 4, 3, 4, 3, 4, 4, 3, 4, 3, 5, 4, 4, 3, 4, 5, 5, 4, 3, 4, 4, 3, 2, 3, 4, 4, 3, 4, 5, 5, 4
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| It is conjectured that all sequence terms are <=5. The terms with a(n)=5 were provided by Edwin Clark (eclark(AT)math.usf.edu).
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REFERENCES
| Robert E. Dressler, Louis Pigno, Robert Young, Sums of squares of primes. Nordisk Mat. Tidskr. 24 (1976), no. 1, 39-40.
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LINKS
| Hugo Pfoertner, Conjectured minimal representations of n by squaresof distinct primes (Table for n<=400).
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EXAMPLE
| The following are representation with the minimal number of terms:
a(0)=4: 0=7^2-11^2-17^2+19^2, a(1)=3: 1=7^2+11^2-13^2, a(4)=1: 4=2^2,
a(5)=2: 5=3^2-2^2, a(6)=5: 6=-(2^2)+3^2+7^2+11^2-13^2.
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CROSSREFS
| Cf. A088934 maximum required prime in representation, A048261, A088908, A088909.
Sequence in context: A178038 A111048 A016700 * A010308 A200625 A156743
Adjacent sequences: A088907 A088908 A088909 * A088911 A088912 A088913
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KEYWORD
| nonn
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AUTHOR
| Hugo Pfoertner (hugo(AT)pfoertner.org), Oct 24 2003
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