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A113798
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Numbers k such that k^2 plus the reverse of k is a square.
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1
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OFFSET
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1,1
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COMMENTS
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a(10) > 1.36*10^14. The sequence contains two infinite sets, 117*1000^k + 2817*(1000^k - 1)/999 and 13101687*1000^k + 114687*(1000^k - 1)/999, for k >= 0. Terms of both sets satisfy the equation rev(x) = 6*x + 9, and thus x^2 + rev(x) = (x+3)^2. - Giovanni Resta, Aug 26 2019
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LINKS
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EXAMPLE
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117^2 + 711 = 120^2, thus 117 is a term.
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CROSSREFS
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KEYWORD
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nonn,base,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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