Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 4500 articles have referenced us, often saying "we would not have discovered this result without the OEIS".
Vincenzo Librandi, Table of n, a(n) for n = 1..10000
a(n) = (1/6)*(10*n^3-9*n^2+5*n).
G.f.: x*(1+5*x+4*x^2)/(1-x)^4. - Colin Barker, Jan 19 2012
(MAGMA) [(1/6)*(10*n^3-9*n^2+5*n): n in [1..40]]; // Vincenzo Librandi, Aug 18 2011
Cf. A004126 = alternate vertex; A000447 = structured diamonds; A100145 for more on structured numbers).
Sequence in context: A139275 A236370 A133547 * A106598 A014816 A147691
Adjacent sequences: A100176 A100177 A100178 * A100180 A100181 A100182
James A. Record (james.record(AT)gmail.com), Nov 07 2004