

A033580


Four times second pentagonal numbers: a(n) = 2*n*(3*n+1).


12



0, 8, 28, 60, 104, 160, 228, 308, 400, 504, 620, 748, 888, 1040, 1204, 1380, 1568, 1768, 1980, 2204, 2440, 2688, 2948, 3220, 3504, 3800, 4108, 4428, 4760, 5104, 5460, 5828, 6208, 6600, 7004, 7420, 7848
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

0,2


COMMENTS

Subsequence of A062717: A010052(6*a(n)+1) = 1.  Reinhard Zumkeller, Feb 21 2011
Sequence found by reading the line from 0, in the direction 0, 8,..., in the square spiral whose vertices are the generalized pentagonal numbers A001318. Opposite numbers to the members of A139267 in the same spiral  Omar E. Pol, Sep 09 2011
a(n) is the number of edges of the octagonal network O(n,n); O(m,n) is defined by Fig. 1 of the Siddiqui et al. reference.  Emeric Deutsch May 13 2018


REFERENCES

M. K. Siddiqui, M. Naeem, N. A. Rahman, and M. Imran, Computing topological indices of certain networks, J. of Optoelectronics and Advanced Materials , 18, No. 910, 2016, 884892.


LINKS

Ivan Panchenko, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (3,3,1).


FORMULA

a(n) = 12*n+a(n1)4 (with a(0)=0).  Vincenzo Librandi, Aug 05 2010
G.f.: 4*x*(2+x)/(1x)^3.  Colin Barker, Feb 13 2012
a(n) = A033579(n).  Michael Somos, Jun 09 2014


PROG

(PARI) a(n)=2*n*(3*n+1) \\ Charles R Greathouse IV, Sep 28 2015


CROSSREFS

Cf. A049451, A045945, A033579, A186423.
Cf. sequences listed in A254963.
Sequence in context: A173681 A045850 A264354 * A299289 A212515 A007331
Adjacent sequences: A033577 A033578 A033579 * A033581 A033582 A033583


KEYWORD

nonn,easy


AUTHOR

N. J. A. Sloane.


STATUS

approved



