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A099186
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Iterated icosahedral numbers: a(0)=1, a(1) = 12, a(n+1)=A006564(a(n)).
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1
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1, 12, 3972, 156624027132, 9605393649115032262909140007773492, 2215570185245038872814956021479696635481690776469126111743280383568619886232750745465064720338596867052
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OFFSET
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0,2
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COMMENTS
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This starts at a(1)=A006564(2)=12. An alternative, for example: if a(1) were set to A006564(3) = 48,
then a(2) = A006564(48) = 270768, a(3) = A006564(270768) = 49628416238058288;
a(4) = A006564(49628416238058288) = 305584454132546884153602392143848716431702444690608 etc.
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REFERENCES
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Conway, J. H. and Guy, R. K. The Book of Numbers. New York: Springer-Verlag, p. 50, 1996.
J. V. Post, "Iterated Triangular Numbers", preprint.
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LINKS
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Table of n, a(n) for n=0..5.
H. K. Kim, On Regular Polytope Numbers, Proc. Amer. Math. Soc. 131 (2003), 65-75. MR 1929024
J. V. Post, Table of Polytope Numbers, Sorted, Through 1,000,000.
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EXAMPLE
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a(2) = A006564(a(1)) = A006564(12) = 12*(5*12^2 - 5*12 + 2)/2 = 3972.
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CROSSREFS
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Cf. A007501, A006564.
Sequence in context: A012609 A159395 A272093 * A307944 A105067 A096732
Adjacent sequences: A099183 A099184 A099185 * A099187 A099188 A099189
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KEYWORD
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easy,nonn
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AUTHOR
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Jonathan Vos Post, Nov 15 2004
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EXTENSIONS
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Definition and comments condensed by R. J. Mathar, Sep 09 2009
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STATUS
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approved
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