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A162465
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Numbers k = x//y which are a concatenation of x and y such that x^3 + y^3 is a multiple of k.
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0
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24, 27, 37, 48, 108, 111, 117, 143, 147, 148, 189, 216, 222, 231, 234, 243, 252, 259, 264, 273, 286, 288, 296, 297, 333, 351, 416, 429, 432, 444, 448, 462, 468, 481, 486, 525, 555, 585, 616, 648, 666, 693, 729, 777, 814, 819, 832, 858, 864, 888, 896, 999
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OFFSET
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1,1
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COMMENTS
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Splicing of k such that y has leading zero digits is not admitted.
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LINKS
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EXAMPLE
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24 = 2//4 is listed because 2^3 + 4^3 = 72 = 3*24.
117 = 1//17 is listed because 1^3 + 17^3 = 1 + 4913 = 4914 = 42*117.
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MAPLE
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Lton := proc(L) add(op(i, L)*10^(i-1), i=1..nops(L)) ; end:
isA162465 := proc(n) dgs := convert(n, base, 10) ; for b from 1 to nops(dgs)-1 do y := Lton([op(1..b, dgs)]) ; x := Lton([op(b+1..nops(dgs), dgs)]) ; if (x^3+y^3) mod n = 0 and op(b, dgs) <> 0 then RETURN(true); fi; od: false; end:
for n from 10 to 1000 do if isA162465(n) then printf("%d, ", n); fi; od: # R. J. Mathar, Sep 16 2009
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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