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A204513
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A204517(n)^2 = floor[A055859(n)/7]: Squares which written in base 7, with some digit appended, yield another square.
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1
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0, 0, 0, 1, 9, 36, 289, 2304, 9216, 73441, 585225, 2340900, 18653761, 148644864, 594579456, 4737981889, 37755210249, 151020840996, 1203428746081, 9589674758400, 38358699033600, 305666163522721, 2435739633423369, 9742958533693476, 77638002106025089, 618668277214777344, 2474673108859109376, 19719746868766849921, 157139306672920022025, 628557226691680088100, 5008738066664673854881, 39912765226644470817024, 159651060906577883268096
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OFFSET
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1,5
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COMMENTS
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Base-7 analog of A202303.
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LINKS
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Table of n, a(n) for n=1..33.
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FORMULA
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G.f. = (x^4 + 9*x^5 + 36*x^6 + 34*x^7 + 9*x^8 + 36*x^9 + x^10)/(1 - 255*x^3 + 255*x^6 - x^9)
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PROG
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(PARI) b=7; for(n=0, 200, issquare(n^2\b) & print1(n^2\b, ", "))
(PARI) A204513(n)=polcoeff((x^4 + 9*x^5 + 36*x^6 + 34*x^7 + 9*x^8 + 36*x^9 + x^10)/(1 - 255*x^3 + 255*x^6 - x^9+O(x^n)), n)
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CROSSREFS
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See also A031149=sqrt(A023110) (base 10), A204502=sqrt(A204503) (base 9), A204514=sqrt(A055872) (base 8), A204516=sqrt(A055859) (base 7), A204518=sqrt(A055851) (base 6), A204520=sqrt(A055812) (base 5), A004275=sqrt(A055808) (base 4), A001075=sqrt(A055793) (base 3), A001541=sqrt(A055792) (base 2).
Sequence in context: A335783 A024120 A262782 * A223306 A272890 A129425
Adjacent sequences: A204510 A204511 A204512 * A204514 A204515 A204516
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KEYWORD
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nonn,base
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AUTHOR
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M. F. Hasler, Jan 15 2012
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STATUS
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approved
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