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Search: id:A018930
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| A018930 |
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Define {b(n)} by b(1)=3, b(n) (n >= 2) is smallest number such that b(1)^2+...+b(n)^2 = m^2 for some m and all b(i) are distinct. Sequence gives values of b(n). |
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6
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| 3, 4, 12, 84, 132, 12324, 1836, 105552, 255084, 197580, 10358340, 13775220, 1936434780, 51299286012, 123205977516, 862441842612, 1310543298204, 667510076211780, 207181940072172, 110912831751840, 1698410314006284
(list; graph; listen)
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OFFSET
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1,1
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MATHEMATICA
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Mathematica program from Jean-Francois ALCOVER, Jan 26 2007:
f[n_]:=Module[{a={3}}, Do[AppendTo[a, First[y/. {ToRules[Reduce[{y^2+a.a == x^2, x>0, y>0}, {y, x}, Integers]]}]], {n-1}]; a]; f[21]//Timing
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CROSSREFS
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Cf. A018928, A018929.
Adjacent sequences: A018927 A018928 A018929 this_sequence A018931 A018932 A018933
Sequence in context: A052626 A122903 A059792 this_sequence A127689 A127690 A092417
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KEYWORD
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nonn
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AUTHOR
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Charles Reed, charles.reed(AT)bbs.ewgateway.org
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EXTENSIONS
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More terms from David W. Wilson (davidwwilson(AT)comcast.net).
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