

A259162


Positive hexagonal numbers (A000384) that are pentagonal numbers (A000326) divided by 2.


3



6, 58311, 559902916, 5376187741821, 51622154137063026, 495675918647891434531, 4759480119234899417304336, 45700527609217585557064800441, 438816461344227137284036796530846, 4213515616126741362983735763224383551, 40458176507232509223142693514443734326556
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OFFSET

1,1


COMMENTS



LINKS



FORMULA

G.f.: x*(x^2+693*x+6) / ((x1)*(x^29602*x+1)).


EXAMPLE

6 is in the sequence because 6 is the 2nd hexagonal number, and 2*6 is the 3rd pentagonal number.


MATHEMATICA

LinearRecurrence[{9603, 9603, 1}, {6, 58311, 559902916}, 20] (* Vincenzo Librandi, Jun 20 2015 *)


PROG

(PARI) Vec(x*(x^2+693*x+6)/((x1)*(x^29602*x+1)) + O(x^20))


CROSSREFS



KEYWORD

nonn,easy


AUTHOR



STATUS

approved



