A060346 Numerators of sequence arising from study of Calabi-Yau manifolds.

-1, -3, -11, -217, -889, -6207, -395583, -11872529, -51190172, -3320575453, -71855148782, -1138862383991, -73603597626136, -585764974480039, -5810293262069806, -9158417736096173491, -75787432383189077231, -289633090947850663933

Offset

0,2

References

P. Candelas et al., A pair of Calabi-yau manifolds as an exactly soluble superconformal theory, Nuclear Phys. B 359 (1991), 21-74 (see p. 73).

Links

Table of n, a(n) for n=0..17.

Example

-1/5, -3/50, -11/375, -217/12500, -889/78125, -6207/781250, ...

Maple

a := proc(n) option remember; local t1; if n<0 then RETURN(0) elif n=0 then RETURN(-1/5) elif n=1 then RETURN(-3/50) else t1 := 125*n*(n-1)*(20*n^2-40*n+23)*a(n-1) -125*(n-1)*(30*n^3-150*n^2+261*n-157)*a(n-2) +(2500*n^4-22500*n^3+76625*n^2-116875*n+67226)*a(n-3) -625*(n-3)^4*a(n-4); t1 := eval(t1); RETURN(t1/( 625*n^2*(n^2-1) )); fi; end;

Crossrefs

Cf. A060347.

Sequence in context: A092840 A007156 A289170 * A145988 A165946 A253639

Adjacent sequences: A060343 A060344 A060345 * A060347 A060348 A060349

Keyword

sign,frac

Author

N. J. A. Sloane, Mar 30 2001

Status

approved