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A180270
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Integers of the form (k^12 - k^8 - k^4 + 1)/512.
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1
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0, 1025, 476073, 27022500, 551536100, 6129324225, 45502479225, 253405810448, 1137920432400, 4322847530025, 14366776735025, 42801847892100, 116415023802948, 293153032943225, 691043521403025, 1538402208782400
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OFFSET
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1,2
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LINKS
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FORMULA
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Integers of the form (k^4+1)*( (k-1)*(k+1)*(k^2+1) )^2/512.
a(n) = ((2*n-1)^4+1)*((n-1)*n*(n^2+(n-1)^2))^2/8 (for k=2n-1).
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EXAMPLE
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a(2) = 1025 is in the sequence because (3^12 - 3^8 - 3^4 + 1)/512 = 524800/512 = 1025.
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MAPLE
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for n from 1 by 2 to 60 do: x:= (n^12-n^8 -n^4+1)/512: printf(`%d, `, x):od: # incomplete program which also prints rationals, R. J. Mathar
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MATHEMATICA
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Select[Table[(k^12-k^8-k^4+1)/512, {k, 40}], IntegerQ] (* Harvey P. Dale, Jan 23 2011 *)
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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Example corrected and general term of the sequence rewritten by Bruno Berselli, Sep 22 2010
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STATUS
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approved
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