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Search: id:A016861
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| 1, 6, 11, 16, 21, 26, 31, 36, 41, 46, 51, 56, 61, 66, 71, 76, 81, 86, 91, 96, 101, 106, 111, 116, 121, 126, 131, 136, 141, 146, 151, 156, 161, 166, 171, 176, 181, 186, 191, 196, 201, 206, 211, 216, 221, 226, 231, 236, 241, 246, 251, 256, 261, 266, 271, 276, 281
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Numbers ending in 1 or 6.
Apart from initial terms, same as 5n-14.
Complement of A047203; A027445(a(n)) mod 10 = 4. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Oct 23 2006
Campbell reference shows: "A graph on n vertices with at least 4n-9 edges is intrinsically linked. A graph on n vertices with at least 5n-14 edges is intrinsically knotted." - Jonathan Vos Post (jvospost3(AT)gmail.com), Jan 18 2007
Central terms of the triangle in A153125: a(n)=A153125(2*n+1,n+1). [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Dec 20 2008]
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LINKS
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Tanya Khovanova, Recursive Sequences
J. Campbell, T.W. Mattman, R. Ottman, J. Pyzer, M. Rodrigues and S. Williams, Intrinsic knotting and linking of almost complete graphs, 15 Jan 2007.
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FORMULA
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G.f.: (1+4*x)/(1-x)^2.
Row sums of triangle A131843 - Gary W. Adamson (qntmpkt(AT)yahoo.com), Jul 21 2007
a(n)=10*n-a(n-1)-13 (with a(1)=1) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 25 2009]
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EXAMPLE
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For n=2, a(2)=10*2-1-13=6; n=3, a(3)=10*3-6-13=11; n=4, a(4)=10*4-11-13=16 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 25 2009]
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MATHEMATICA
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f[n_]:=5*n+1; lst={}; Do[a=f[n]; AppendTo[lst, a], {n, 0, 6!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Jun 25 2009]
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PROGRAM
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(Other) sage: [i+1 for i in range(285) if gcd(i, 5) == 5] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 20 2009]
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CROSSREFS
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Cf. A093562 ((5, 1) Pascal, column m=1).
Cf. A131843.
Sequence in context: A081746 A080900 A080783 this_sequence A145287 A140232 A085813
Adjacent sequences: A016858 A016859 A016860 this_sequence A016862 A016863 A016864
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KEYWORD
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nonn,easy,new
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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More terms from Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Oct 23 2006
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