OFFSET
0,3
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..500
F. Bergeron, L. Favreau and D. Krob, Conjectures on the enumeration of tableaux of bounded height, Discrete Math, vol. 139, no. 1-3 (1995), 463-468.
Simone Severini and Ferenc Szollosi, A further look into combinatorial orthogonality, arXiv:0709.3651 [math.CO], 2007-2008. Mentions this sequence, see p. 7.
Wikipedia, Hook length formula.
FORMULA
sum_lambda f_lambda^3 where the sum is over lambda partitions of length less than or equal to 3 and f_lambda is the number of standard tableaux of shape lambda
EXAMPLE
f_111 = f_3 = 1, f_21 = 2 therefore a(3) = f_111^3 + f_21^3 + f_3^3 = 1+8+1 = 10
PROG
(PARI) \\ HLF is hook length formula of partition.
HLF(p) = { my(v=vector(if(#p, p[#p], 0)), r=1); p=vecsort(p); for(i=1, #p, my(t=p[i]); for(j=1, t, v[j]++; r *= v[j] + t - j )); vecsum(v)!/r }
a(n) = { my(s=0); forpart(p=n, s+=HLF(p)^3, , 3); s } \\ Andrew Howroyd, Jul 05 2026
CROSSREFS
KEYWORD
nonn,changed
AUTHOR
Mike Zabrocki, Mar 30 2007
EXTENSIONS
a(19) onward from Andrew Howroyd, Jul 05 2026
STATUS
approved
