A100162 Structured disdyakis dodecahedral numbers (vertex structure 7).

1, 26, 117, 316, 665, 1206, 1981, 3032, 4401, 6130, 8261, 10836, 13897, 17486, 21645, 26416, 31841, 37962, 44821, 52460, 60921, 70246, 80477, 91656, 103825, 117026, 131301, 146692, 163241, 180990, 199981, 220256

Offset

1,2

Comments

Also structured deltoidal icositetrahedral numbers (vertex structure 7) (cf. A100161 = alternate vertex).

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..5000

Formula

a(n) = (1/6)*(42*n^3 - 54*n^2 + 18*n).

G.f.: x*(1 + 22*x + 19*x^2)/(1-x)^4. - Colin Barker, Jan 19 2012

Prog

(Magma) [(1/6)*(42*n^3-54*n^2+18*n): n in [1..40]]; // Vincenzo Librandi, Jul 24 2011

Crossrefs

Cf. A100161, A100163 = alternate vertices; A100145 for more on structured polyhedral numbers.

Cf. A260260 (comment). - Bruno Berselli, Jul 22 2015

Sequence in context: A251262 A221570 A100161 * A051729 A100163 A296325

Adjacent sequences: A100159 A100160 A100161 * A100163 A100164 A100165

Keyword

nonn,easy

Author

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

Status

approved