login
Structured tetrakis hexahedral numbers (vertex structure 5).
3

%I #17 Sep 08 2022 08:45:15

%S 1,14,59,156,325,586,959,1464,2121,2950,3971,5204,6669,8386,10375,

%T 12656,15249,18174,21451,25100,29141,33594,38479,43816,49625,55926,

%U 62739,70084,77981,86450,95511,105184

%N Structured tetrakis hexahedral numbers (vertex structure 5).

%H Vincenzo Librandi, <a href="/A100174/b100174.txt">Table of n, a(n) for n = 1..10000</a>

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1).

%F a(n) = (1/6)*(20*n^3 - 24*n^2 + 10*n).

%F G.f.: x*(1+x)*(1+9*x)/(1-x)^4. [_Colin Barker_, May 29 2012]

%o (Magma) [(1/6)*(20*n^3-24*n^2+10*n): n in [1..50] ]; // _Vincenzo Librandi_, Aug 02 2011

%Y Cf. A005915 = alternate vertex; cf. A100145 for more on structured numbers.

%K easy,nonn

%O 1,2

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

%E Formula corrected by Helena Verrill (verrill(AT)math.lsu.edu), Mar 23 2007