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A077020
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a(n) is the unique odd positive solution x of 2^n = 7x^2+y^2.
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9
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1, 1, 1, 3, 1, 5, 7, 3, 17, 11, 23, 45, 1, 91, 89, 93, 271, 85, 457, 627, 287, 1541, 967, 2115, 4049, 181, 8279, 7917, 8641, 24475, 7193, 41757, 56143, 27371, 139657, 84915, 194399, 364229, 24569, 753027, 703889, 802165, 2209943, 605613
(list; graph; refs; listen; history; internal format)
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OFFSET
| 3,4
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COMMENTS
| The sequences A001607, A077020, A107920, A167433, A169998 are all essentially the same except for signs.
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REFERENCES
| A. Engel, Problem-Solving Strategies. p. 126.
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LINKS
| T. D. Noe, Table of n, a(n) for n=3..500
Eric Weisstein's World of Mathematics, Diophantine Equations 2nd Powers
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EXAMPLE
| a(3)=1 since 2^3=8=7*1^2+1^2, a(6)=3 since 2^6=64=7*3^2+1^2.
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CROSSREFS
| a(n)=abs(A001607(n-2)).
Cf. A077021.
Sequence in context: A188146 A001607 A167433 * A107920 A169998 A171998
Adjacent sequences: A077017 A077018 A077019 * A077021 A077022 A077023
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KEYWORD
| nonn
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AUTHOR
| Ed Pegg Jr. (ed(AT)mathpuzzle.com), Oct 17, 2002
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