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A204512
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Square roots of [A055872/8]: Their square written in base 8, with some digit appended, is again a square.
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8
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0, 0, 0, 1, 2, 6, 12, 35, 70, 204, 408, 1189, 2378, 6930, 13860, 40391, 80782, 235416, 470832, 1372105, 2744210, 7997214, 15994428, 46611179, 93222358, 271669860, 543339720, 1583407981, 3166815962, 9228778026, 18457556052, 53789260175, 107578520350
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OFFSET
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1,5
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COMMENTS
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LINKS
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FORMULA
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G.f. = x^4*(1 + 2*x)/(1 - 6*x^2 + x^4)
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MATHEMATICA
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CoefficientList[Series[(x^4 (1+2x))/(1-6x^2+x^4), {x, 0, 40}], x] (* Harvey P. Dale, Nov 30 2020 *)
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PROG
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(PARI) b=8; for(n=1, 1e7, issquare(n^2\b) & print1(sqrtint(n^2\b)", "))
(PARI) a(n)=polcoeff((2*x^5 + x^4)/(x^4 - 6*x^2 + 1+O(x^n)), n)
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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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STATUS
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approved
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