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A100186 Structured heptagonal anti-diamond numbers (vertex structure 7). 3
1, 16, 67, 176, 365, 656, 1071, 1632, 2361, 3280, 4411, 5776, 7397, 9296, 11495, 14016, 16881, 20112, 23731, 27760, 32221, 37136, 42527, 48416, 54825, 61776, 69291, 77392, 86101, 95440, 105431, 116096 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = (1/6)*(22*n^3-24*n^2+8*n).

G.f.: x*(1+12*x+9*x^2)/(1-x)^4. - Colin Barker, Jan 19 2012

PROG

(MAGMA) [(1/6)*(22*n^3-24*n^2+8*n): n in [1..40]]; // Vincenzo Librandi, Aug 18 2011

CROSSREFS

Cf. A063521 = alternate vertex; A100188 = structured anti-diamonds; A100145 for more on structured numbers.

Sequence in context: A043153 A039330 A043933 * A178574 A005906 A200839

Adjacent sequences:  A100183 A100184 A100185 * A100187 A100188 A100189

KEYWORD

nonn,easy

AUTHOR

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

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Last modified February 17 23:54 EST 2012. Contains 206085 sequences.