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 A359006 Euler characteristics of some Calabi-Yau n-folds. 0
 2, 0, 24, -296, 5910, -147624, 4482044, -160180656, 6588215370, -306553312880, 15921704570112, -913109351334168, 57312158437875614, -3907821040411155672, 287639624919939481380, -22731972554599539494624, 1919809166125424793288978, -172552913868209944831000416 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS These numbers are Euler characteristics of Calabi-Yau subvarieties in some weighted projective spaces. See formula B.8 in Bourjaily et alii. a(n) is divisible by n. LINKS Table of n, a(n) for n=1..18. Jacob L. Bourjaily, Andrew J. McLeod, Cristian Vergu, Matthias Volk, Matt von Hippel, and Matthias Wilhelm, Embedding Feynman Integral (Calabi-Yau) Geometries in Weighted Projective Space, arXiv:1910.01534 [hep-th], 2019-2020. FORMULA a(n) = (1-(1-2*n)^n+2*n^2)/(2*n). PROG (Sage) [(1-(1-2*n)**n+2*n**2)/n/2 for n in range(1, 18)] CROSSREFS Sequence in context: A109582 A308506 A255162 * A097563 A360643 A158045 Adjacent sequences: A359003 A359004 A359005 * A359007 A359008 A359009 KEYWORD sign,easy AUTHOR F. Chapoton, Dec 10 2022 STATUS approved

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Last modified August 13 14:39 EDT 2024. Contains 375142 sequences. (Running on oeis4.)