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A034178
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Number of solutions to n = a^2-b^2, a>b>=0.
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7
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1, 0, 1, 1, 1, 0, 1, 1, 2, 0, 1, 1, 1, 0, 2, 2, 1, 0, 1, 1, 2, 0, 1, 2, 2, 0, 2, 1, 1, 0, 1, 2, 2, 0, 2, 2, 1, 0, 2, 2, 1, 0, 1, 1, 3, 0, 1, 3, 2, 0, 2, 1, 1, 0, 2, 2, 2, 0, 1, 2, 1, 0, 3, 3, 2, 0, 1, 1, 2, 0, 1, 3, 1, 0, 3, 1, 2, 0, 1, 3, 3, 0, 1, 2, 2, 0, 2, 2, 1, 0, 2, 1, 2, 0, 2, 4, 1, 0, 3
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,9
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COMMENTS
| Also, number of ways n can be expressed as the sum of consecutive odd numbers.(e.g. 45 = 45 = 13+15+17 = 5+7+9+11+13, so a(45)=3). - Naohiro Nomoto (n_nomoto(AT)yabumi.com), Feb 26 2002
a(A042965(n))>0, a(A016825(n))=0; also number of occurrences of n in A094728. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), May 24 2004
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LINKS
| T. D. Noe, Table of n, a(n) for n=1..2000
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FORMULA
| a(2k) = A038548(2k)-A001227(k). a(2k+1) = A038548(2k+1). - Naohiro Nomoto (n_nomoto(AT)yabumi.com), Feb 26 2002
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MATHEMATICA
| nn = 100; Table[0, {nn}]; Do[n = a^2 - b^2; If[n <= nn, t[[n]]++], {a, nn}, {b, 0, a - 1}]] (* T. D. Noe, May 04 2011 *)
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CROSSREFS
| Cf. A058957, A016825.
Sequence in context: A086971 A088434 A205745 * A074169 A099362 A058940
Adjacent sequences: A034175 A034176 A034177 * A034179 A034180 A034181
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KEYWORD
| easy,nonn,nice
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AUTHOR
| Erich Friedman (erich.friedman(AT)stetson.edu)
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