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A254474 30-gonal numbers: a(n) = n*(14*n-13). 15
0, 1, 30, 87, 172, 285, 426, 595, 792, 1017, 1270, 1551, 1860, 2197, 2562, 2955, 3376, 3825, 4302, 4807, 5340, 5901, 6490, 7107, 7752, 8425, 9126, 9855, 10612, 11397, 12210, 13051, 13920, 14817, 15742, 16695, 17676, 18685, 19722, 20787, 21880 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
See comments in A255184.
Also star 15-gonal numbers.
REFERENCES
E. Deza and M. M. Deza, Figurate numbers, World Scientific Publishing (2012), page 6 (28th row of the table).
LINKS
Luciano Ancora, Polygonal and Pyramidal numbers, Section 1.
FORMULA
G.f.: x*(-1 - 27*x)/(-1 + x)^3.
a(n) = A000217(n) + 27*A000217(n-1).
a(n) = A051867(n) + 15*A000217(n-1).
Product_{n>=2} (1 - 1/a(n)) = 14/15. - Amiram Eldar, Jan 22 2021
E.g.f.: exp(x)*(x + 14*x^2). - Nikolaos Pantelidis, Feb 05 2023
MATHEMATICA
Table[n (14 n - 13), {n, 40}]
PROG
(PARI) a(n)=n*(14*n-13) \\ Charles R Greathouse IV, Jun 17 2017
CROSSREFS
Cf. similar sequences listed in A255184.
Sequence in context: A130862 A070756 A058903 * A103906 A124799 A126384
KEYWORD
nonn,easy
AUTHOR
Luciano Ancora, Apr 04 2015
STATUS
approved

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Last modified February 28 08:45 EST 2024. Contains 370393 sequences. (Running on oeis4.)