

A100175


Structured triakis tetrahedral numbers (vertex structure 4).


6



1, 8, 30, 76, 155, 276, 448, 680, 981, 1360, 1826, 2388, 3055, 3836, 4740, 5776, 6953, 8280, 9766, 11420, 13251, 15268, 17480, 19896, 22525, 25376, 28458, 31780, 35351, 39180, 43276, 47648, 52305, 57256, 62510, 68076, 73963, 80180, 86736, 93640, 100901, 108528
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OFFSET

1,2


COMMENTS

Equals binomial transform of [1, 7, 15, 9, 0, 0, 0,...] where (1, 7, 15, 9) = row 3 of triangle A038763.  Gary W. Adamson, Jul 19 2008
Equals convolution square of 1, 4, 7, 10, 13, 16, 19,..., A016777.  Gary W. Adamson, Jul 28 2009


LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..10000
Index entries for linear recurrences with constant coefficients, signature (4,6,4,1).


FORMULA

a(n) = (3*n^33*n^2+2*n)/2.
G.f.: x*(2*x+1)^2 / ( (x1)^4 ).


PROG

(MAGMA) [(3*n^33*n^2+2*n)/2: n in [1..50] ]; // Vincenzo Librandi, Aug 02 2011


CROSSREFS

Cf. A000578 = alternate vertex; A100145 for more on structured numbers.
Cf. A038763.
Sequence in context: A131769 A055832 A195753 * A063489 A299284 A002417
Adjacent sequences: A100172 A100173 A100174 * A100176 A100177 A100178


KEYWORD

easy,nonn


AUTHOR

James A. Record (james.record(AT)gmail.com), Nov 07 2004


STATUS

approved



