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A140657
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Powers of 2 with 3 alternatingly added and subtracted.
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4
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4, -1, 7, 5, 19, 29, 67, 125, 259, 509, 1027, 2045, 4099, 8189, 16387, 32765, 65539, 131069, 262147, 524285, 1048579, 2097149, 4194307, 8388605, 16777219, 33554429, 67108867, 134217725, 268435459, 536870909, 1073741827, 2147483645, 4294967299, 8589934589
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OFFSET
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0,1
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LINKS
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FORMULA
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a(n) + a(n+1) = 3^*2^n = A007283(n).
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MATHEMATICA
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LinearRecurrence[{1, 2}, {4, -1}, 40] (* or *) Total/@Partition[Riffle[ Table[ 2^n, {n, 0, 40}], {3, -3}], 2] (* Harvey P. Dale, Nov 13 2014 *)
CoefficientList[Series[(4 - 5 x) / ((1 + x) (1 - 2 x)), {x, 0, 50}], x] (* Vincenzo Librandi, Jan 14 2015 *)
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PROG
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CROSSREFS
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KEYWORD
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sign,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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