

A000373


Conjectured dimension of a module associated with the free commutative Moufang loop with n generators.


1



0, 0, 1, 8, 44, 214, 1000, 4592, 20888, 94846, 434973, 2042836, 9979086, 51460622, 283839957, 1688139424, 10859199656, 75338888918, 560740210491, 4445766353604, 37329808482989, 330143634313064, 3064464030121369
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OFFSET

1,4


COMMENTS

There is an explicit formula for the nth term of this sequence (see Eq. (8.4) of Smith (1982)). It is conjectured that this gives the answer to a question of Manin about the dimension of a certain module associated with the free commutative Moufang loop with n generators.  N. J. A. Sloane, May 21 2014


REFERENCES

Yu. I. Manin, Cubic Forms, Second edition, NorthHolland Publishing Co., Amsterdam, 1986, page 312. MR0833513 (87d:11037)
Smith, Jonathan D. H.; Commutative Moufang loops and Bessel functions. Invent. Math. 67 (1982), no. 1, 173187.


LINKS

Table of n, a(n) for n=1..23.


EXAMPLE

G.f. = x^3 + 8*x^4 + 44*x^5 + 214*x^6 + 1000*x^7 + 4592*x^8 + 20888*x^9 + ...


PROG

(PARI) {a(n) = local(A); if( n<3, 0, A = Vec(1 + serlaplace( serlaplace( subst( 1 / besselj(0, x + O(x^n)), x^2, 4*x)))); A[1] = 0; sum(k=1, (n1)\2, sum(p=0, n  2*k  1, n! / p! / (2*k+1)! / (n  p  2*k 1 )! * (A[k] + binomial( p+k1, k1)))))}; /* Michael Somos, May 17 2004 */


CROSSREFS

Sequence in context: A270678 A292487 A125318 * A176688 A272154 A270935
Adjacent sequences: A000370 A000371 A000372 * A000374 A000375 A000376


KEYWORD

nonn


AUTHOR

N. J. A. Sloane


STATUS

approved



