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A180241
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Numbers whose square can be expressed as the sum of a square, a cube and a fourth power, all positive.
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10
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5, 7, 8, 9, 12, 17, 18, 19, 21, 22, 23, 24, 25, 28, 31, 32, 33, 35, 37, 38, 39, 41, 42, 44, 45, 46, 47, 51, 52, 53, 54, 55, 57, 59, 60, 61, 63, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 77, 78, 79, 80, 81, 82, 83, 84, 85, 87, 88, 89, 90, 91, 93, 95, 96, 97, 98, 99, 100, 101
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OFFSET
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1,1
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COMMENTS
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a(n)^2 = x^2 + y^3 + z^4 with x,y,z > 0.
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LINKS
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EXAMPLE
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a(5) = 12 is a term since 12*12 = 144 = 6^2 + 3^3 + 3^4 = 36 + 27 + 81.
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PROG
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(PARI) for(D=1, 99, for(C=1, sqrtn(D^2-1, 4), for(B=1, sqrtn(D^2-C^4-1, 3), issquare(D^2-C^4-B^3, &A)&&print1([A, B, C, D][4]", ")+next(3)))) \\ M. F. Hasler, Apr 06 2015
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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