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A061877
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|First digit - second digit + third digit - fourth digit ...| = 8.
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1
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8, 19, 80, 91, 107, 118, 129, 190, 206, 217, 228, 239, 305, 316, 327, 338, 349, 404, 415, 426, 437, 448, 459, 503, 514, 525, 536, 547, 558, 569, 602, 613, 624, 635, 646, 657, 668, 679, 701, 712, 723, 734, 745, 756, 767, 778, 789, 800, 811, 822, 833, 844, 855
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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Do[ a = IntegerDigits[ n ]; l = Length[ a ]; e = o = {}; Do[ o = Append[ o, a[[ 2k - 1 ]]], {k, 1, l/2 + .5} ]; Do[ e = Append[ e, a[[ 2k ] ]], {k, 1, l/2} ]; If[ Abs[ Apply[ Plus, o ] - Apply[ Plus, e ]] == 8, Print[ n ]], {n, 1, 1000} ]
Select[Range[1000], Abs[Total[Times@@@Partition[Riffle[IntegerDigits[#], {1, -1}, {2, -1, 2}], 2]]]==8&] (* Harvey P. Dale, Jan 28 2019 *)
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PROG
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(Python)
def ok(n): return abs(sum((-1)**i*int(d) for i, d in enumerate(str(n))))==8
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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