OFFSET
1,2
LINKS
M. Baake and R. V. Moody, Similarity submodules and root systems in four dimensions, Canad. J. Math. (1999), 51 1258-1276.
Research Group Michael Baake, Preprints
PROG
(PARI) g(p, e) = (e+1)*p^e + 2*(1-(e+1)*p^e+e*p^(e+1))/(p-1)^2;
fpa(p, e) = {if (p == 2, g(2, e), if (((p % 8) == 3) || ((p % 8) == 5), if (e % 2, 0, g(p^2, e/2)), if (((p % 8) == 1) || ((p % 8) == 7), sum(s=0, e, g(p, s)*g(p, e-s))))); }
za(n) = {my(f = factor(n)); prod(i=1, #f~, fpa(f[i, 1], f[i, 2])); }
lista(nn) = {for (n=1, nn, if (v = za(n), print1(v, ", ")); ); } \\ Michel Marcus, Mar 03 2014
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
EXTENSIONS
More terms from Michel Marcus, Mar 03 2014
STATUS
approved