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A061876
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|First digit - second digit + third digit - fourth digit ...| = 7.
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1
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7, 18, 29, 70, 81, 92, 106, 117, 128, 139, 180, 191, 205, 216, 227, 238, 249, 290, 304, 315, 326, 337, 348, 359, 403, 414, 425, 436, 447, 458, 469, 502, 513, 524, 535, 546, 557, 568, 579, 601, 612, 623, 634, 645, 656, 667, 678, 689, 700, 711, 722, 733, 744
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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 ]] == 7, Print[ n ]], {n, 1, 1000} ]
Select[Range[1000], Abs[Total[Times@@@Partition[Riffle[IntegerDigits[#], {1, -1}, {2, -1, 2}], 2]]]==7&] (* Harvey P. Dale, Jan 05 2013 *)
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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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