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A259160 Positive squares (A000290) that are octagonal numbers (A000567) divided by 2. 3
4, 39204, 376437604, 3614553835204, 34706945549192004, 333256087548787788004, 3199924917936514791223204, 30725678728770327476537417604, 295027963953727766493197492611204, 2832858479158015285097354847515364004, 27201106821847298813777034752645032556004 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Intersection of A000290 and A033579 (even octagonal numbers divided by 2). - Michel Marcus, Jun 20 2015
LINKS
FORMULA
G.f.: -4*x*(x^2+198*x+1) / ((x-1)*(x^2-9602*x+1)).
EXAMPLE
4 is in the sequence because 4 is the 2nd square, and 2*4 is the 2nd octagonal number.
MATHEMATICA
LinearRecurrence[{9603, -9603, 1}, {4, 39204, 376437604}, 20] (* Vincenzo Librandi, Jun 20 2015 *)
PROG
(PARI) Vec(-4*x*(x^2+198*x+1)/((x-1)*(x^2-9602*x+1)) + O(x^20))
CROSSREFS
Sequence in context: A275684 A001376 A053937 * A173138 A275587 A132638
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Jun 19 2015
STATUS
approved

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Last modified March 28 18:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)