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A092357
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Smallest value of x=a+b+c+d (a,b,c,d positive integers) such that there are n different values of m=a^2+b^2=c^2+d^2, or 0 if no such x exists.
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2
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18, 30, 36, 42, 54, 66, 78, 60, 80, 102, 72, 84, 138, 112, 90, 184, 154, 186, 452, 170, 126, 162, 196, 160, 120, 150, 652, 144, 692, 344, 318, 376, 266, 192, 200, 168, 272, 228, 304, 220, 472, 426, 234, 1052, 1076, 180, 474, 260, 368, 722, 584, 418, 534, 434
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| This is an infinite sequence because if x=4*p (p=any prime), the number of different n values of m is n=k for p=6k+/-1. I do not know if there is an x for every natural number n.
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EXAMPLE
| We denote m=a^2+b^2=c^2+d^2 by writing (a,b,c,d). Then:
x=18->(1,7,5,5)=50 for n=1
x=30->(1,12,8,9)=145 (3,11,7,9)=130 for n=2
x=36->(2,14,10,10)=200 (3,14,6,13)=205 (4,13,8,11)=185 for n=3
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CROSSREFS
| Cf. A091459 A090073.
Sequence in context: A151700 A154367 A161164 * A141115 A039320 A043143
Adjacent sequences: A092354 A092355 A092356 * A092358 A092359 A092360
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KEYWORD
| nonn
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AUTHOR
| Robin Garcia (verob99(AT)teleline.es), Mar 18 2004
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EXTENSIONS
| More terms from Ray Chandler (rayjchandler(AT)sbcglobal.net), Mar 26 2004
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