

A130896


For D_n type groups as polyhedra that are pyramidlike: {F,V,E,dimension}>{2*n+1,2*n+1,2*n,(2*n+1)*((2*n+1)1)/2} such that Euler's equation is true: V=EF+2.


0



3, 3, 4, 3, 5, 5, 8, 10, 7, 7, 12, 21, 9, 9, 16, 36, 11, 11, 20, 55, 13, 13, 24, 78, 15, 15, 28, 105, 17, 17, 32, 136, 19, 19, 36, 171, 21, 21, 40, 210, 23, 23, 44, 253, 25, 25, 48, 300, 27, 27, 52, 351, 29, 29, 56, 406, 31, 31, 60, 465, 33, 33, 64, 528, 35, 35, 68, 595, 37, 37
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OFFSET

1,1


COMMENTS

This idea comes from the Octahedron being truncated by one vertex to give a pyramid. In this case the n=1 is not a 3d polyhedron, but the rest are very simple F=E figures. Adding one vertex below the plane of the major polygon gives an D_nh type point group ( D_n like figures A131498): these figures are Point groups C_nv.


REFERENCES

David M. Bishop, Group Theory and Chemistry,Dover Publications, 1993, table 37.1, page 46


LINKS

Table of n, a(n) for n=1..70.


FORMULA

{a(n),a(n+1),a(n+2),a(n+3) = {2*m+1,2*m+1,4*m,(2*m+1)*((2*m+1)1)/2}: m=Floor[n/4]


MATHEMATICA

a = Table[{2*n + 1, 2*n + 1, 4*n, (2*n + 1)*((2*n + 1)  1)/2}, {n, 1, 32}]; Flatten[a]


CROSSREFS

Cf. A131498.
Sequence in context: A316662 A123708 A102302 * A254279 A029882 A163523
Adjacent sequences: A130893 A130894 A130895 * A130897 A130898 A130899


KEYWORD

nonn


AUTHOR

Roger L. Bagula, Aug 22 2007


STATUS

approved



