

A325301


a(n) is the number of edges of the step pyramid with n levels described in A245092.


2



12, 21, 36, 51, 63, 84, 96, 117, 138, 165, 177, 204, 216, 240, 273, 306, 318, 351, 363
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OFFSET

1,1


COMMENTS

To calculate a(n) consider that levels greater than n do not exist.


LINKS

Table of n, a(n) for n=1..19.
Omar E. Pol, Perspective view of the pyramid (first 16 levels)


FORMULA

a(n) = A325300(n) + A325302(n)  2 (Euler's formula).


EXAMPLE

For n = 1 the first level of the step pyramid (starting from the top) is a cube, and a cube has 12 edges, so a(1) = 12.


CROSSREFS

Cf. A325300 (number of faces), A325302 (number of vertices).
Cf. A196020, A235791, A236104, A237270, A237271, A237591, A237593, A245092, A262626, A294848, A294849, A317109, A323648.
Sequence in context: A071263 A241503 A226186 * A219542 A137480 A316267
Adjacent sequences: A325298 A325299 A325300 * A325302 A325303 A325304


KEYWORD

nonn,more


AUTHOR

Omar E. Pol, Apr 16 2019


STATUS

approved



