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 A091572 Poincaré series [or Poincare series] of the preprojective algebra of an extended Dynkin diagram of type E_7. 6
 8, 14, 20, 26, 34, 40, 48, 54, 62, 66, 74, 80, 90, 94, 102, 106, 116, 120, 130, 134, 144, 146, 156, 160, 172, 174, 184, 186, 198, 200, 212, 214, 226, 226, 238, 240, 254, 254, 266, 266, 280, 280, 294, 294, 308, 306, 320, 320, 336, 334, 348, 346, 362, 360, 376 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 REFERENCES I, Reiten, Dynkin diagrams and the representation theory of algebras, Notices of the AMS, Vol. 44, No 5. LINKS FORMULA a(n) = 6*(n+1) + 2*A087504(n). G.f.: (6/(1-x)^2)+2*(1-x^9)/((1-x^4)*(1-x^6)*(1-x)). MATHEMATICA CoefficientList[ Series[ (8 + 6x + 6x^2 + 14x^3 + 6x^4 + 6x^5 + 8x^6) / (1 - x + x^3 - 2x^4 + x^5 - x^7 + x^8), {x, 0, 54}], x] (* Jean-François Alcover, Dec 02 2011 *) CROSSREFS Cf. A087504, A091571, A091573, A091574, A091575, A091576, A091577. Sequence in context: A136798 A172182 A091575 * A096786 A114527 A345089 Adjacent sequences:  A091569 A091570 A091571 * A091573 A091574 A091575 KEYWORD easy,nonn AUTHOR Paul Boddington, Jan 22 2004 STATUS approved

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Last modified June 19 04:53 EDT 2021. Contains 345125 sequences. (Running on oeis4.)