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A259658
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Let f(x) be the absolute value of the difference between x and its base-2 reversal. Let g(x) be the number of times f(x) must be applied to x for the result to be 0. a(n) is the smallest value of x for which g(x) is n.
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1
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0, 1, 2, 11, 38, 271, 544, 2093, 2624, 8607, 17984, 35343, 35904, 70671, 71744, 141327, 143424, 282639, 286784, 565263, 573504, 1130511, 1146944, 2261007, 2293824, 4521999, 4587584, 9043983, 9175104, 18087951, 18350144, 36175887, 36700224, 72351759, 73400384
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OFFSET
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0,3
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COMMENTS
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LINKS
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FORMULA
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G.f.: -x*(18144*x^12 +12800*x^11 -13708*x^10 -11200*x^9 -2870*x^8 -1068*x^7 -1302*x^6 -434*x^5 -240*x^4 -32*x^3 -8*x^2 -2*x-1)/ ((x-1) *(x+1) *(2*x^2-1)). - Alois P. Heinz, Jul 02 2015
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MATHEMATICA
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CoefficientList[Series[x (18144 x^12 + 12800 x^11 - 13708 x^10 -11200 x^9 - 2870 x^8 - 1068 x^7 - 1302 x^6 - 434 x^5 - 240 x^4 - 32 x^3 - 8 x^2 - 2 x - 1)/((1 - x) (x + 1) (2 x^2 - 1)), {x, 0, 50}], x] (* Vincenzo Librandi, Jul 10 2015 *)
LinearRecurrence[{0, 3, 0, -2}, {0, 1, 2, 11, 38, 271, 544, 2093, 2624, 8607, 17984, 35343, 35904, 70671}, 50] (* Harvey P. Dale, Nov 23 2022 *)
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PROG
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(Magma) I:=[0, 1, 2, 11, 38, 271, 544, 2093, 2624, 8607, 17984, 35343, 35904, 70671]; [n le 14 select I[n] else 3*Self(n-2)-2*Self(n-4): n in [1..50]]; // Vincenzo Librandi, Jul 10 2015
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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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EXTENSIONS
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STATUS
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approved
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