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Search: id:A047470
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| A047470 |
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Numbers that are congruent to {0, 3} mod 8. |
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+0
2
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| 0, 3, 8, 11, 16, 19, 24, 27, 32, 35, 40, 43, 48, 51, 56, 59, 64, 67, 72, 75, 80, 83, 88, 91, 96, 99, 104, 107, 112, 115, 120, 123, 128, 131, 136, 139, 144, 147, 152, 155, 160, 163, 168, 171, 176, 179, 184, 187, 192
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Maximum number of squares attacked by a queen on an n X n chessboard - Stewart Gordon (smjg(AT)iname.com), Mar 23 2001
Number of squares attacked by a queen on a toroidal chessboard - Diego Torres (torresvillarroel(AT)hotmail.com), May 19 2001
List of squared distances between points of diamond 'lattice' with minimal distance sqrt(3) - Arnold Neumaier (Arnold.Neumaier(AT)univie.ac.at), Aug 01 2003
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FORMULA
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a(n) = a(n-1) + 4 + (-1)^n = a(n-1) + a(n-2) - a(n-3) = A042948(n) + A005843(n); g.f.: (3x+5*x^2)/((1-x)*(1-x^2)).
a(n)=8*n-a(n-1)-13 (with a(1)=0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 24 2009]
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EXAMPLE
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For n=2, a(2)=8*2-0-13=3; n=3, a(3)=8*3-3-13=8; n=4, a(4)=8*4-8-13=11 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 24 2009]
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MAPLE
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a:=n->add(4+(-1)^j, j=1..n):seq(a(n), n=0..64); # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Dec 13 2008]
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CROSSREFS
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Cf. A042948.
Sequence in context: A145837 A111132 A003234 this_sequence A003623 A058572 A154485
Adjacent sequences: A047467 A047468 A047469 this_sequence A047471 A047472 A047473
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KEYWORD
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nonn,new
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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