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Search: id:A008782
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| A008782 |
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For any circular arrangement of 0..n-1, let S = sum of squares of every sum of three contiguous numbers; then a(n) = # of distinct values of S. |
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+0
2
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OFFSET
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1,5
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MAPLE
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A008782 := proc(n) local S, i, j, sumsq, npermut, p, per ; S := {} ; npermut := combinat[permute]([seq(i, i=0..n-1)]) ; for p from 1 to nops(npermut) do per := op(p, npermut) ; sumsq := 0 ; for i from 0 to n-1 do sumsq := sumsq + (add(op(1+(j mod n), per), j=i..i+2)) ^2 ; od ; S := S union {sumsq} ; od ; RETURN(nops(S)) ; end: for n from 1 to 20 do print(A008782(n)) ; od : - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jun 18 2007
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CROSSREFS
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Cf. A007773.
Sequence in context: A041124 A048695 A111325 this_sequence A097058 A134790 A097405
Adjacent sequences: A008779 A008780 A008781 this_sequence A008783 A008784 A008785
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KEYWORD
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nonn,more
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AUTHOR
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Olivier Gerard (ogerard(AT)ext.jussieu.fr)
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EXTENSIONS
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More terms from Reiner Martin (reinermartin(AT)hotmail.com), May 19 2001
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