

A133328


Values of n such that the sum of the 7gonal number (5*n^2  3*n)/2 and the following 7gonal number is a 7gonal number.


3



0, 170, 13622, 6672192, 534017484, 261563278454, 20934553401986, 10253803635289356, 820676361930645528, 401969609849050063298, 32172154719470612594510, 15758012635048656946126680, 1261212808492010592999343332, 617745610917207839753008053902
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OFFSET

1,2


COMMENTS

Both bisections of the sequence satisfy the recurrence relation a(n+2) = 39202*a(n+1)  a(n) + 7840.
Also nonnegative integers x in the solution to 10*x^25*y^2+4*x+3*y+2 = 0, the corresponding values of y being A133327.  Colin Barker, Dec 05 2014


LINKS



FORMULA

G.f.: 2*x^2*(6*x^3+2885*x^26726*x85) / ((x1)*(x^2198*x+1)*(x^2+198*x+1)).  Colin Barker, Dec 05 2014


PROG

(PARI) concat(0, Vec(2*x^2*(6*x^3+2885*x^26726*x85)/((x1)*(x^2198*x+1)*(x^2+198*x+1)) + O(x^100))) \\ Colin Barker, Dec 05 2014


CROSSREFS



KEYWORD

nonn,easy


AUTHOR



EXTENSIONS



STATUS

approved



