OFFSET
1,2
COMMENTS
LINKS
Rémy Sigrist, Table of n, a(n) for n = 1..10000
Rémy Sigrist, Colored logarithmic scatterplot of the first 100000 terms (where the color is function of A001222(n))
FORMULA
EXAMPLE
For n = 12:
- 12 = 2^2 * 3 = prime(1+0)^2 * prime(1+1),
- f(12) = 2 + x,
- f(12)^2 = 4 + 4*x + x^2,
- a(12) = prime(1+0)^4 * prime(1+1)^4 * prime(1+2) = 2^4 * 3^4 * 5 = 6480.
PROG
(PARI) a(n) = my (f=factor(n), p=apply(primepi, f[, 1]~)); prod (i=1, #p, prod(j=1, #p, prime(p[i]+p[j]-1)^(f[i, 2]*f[j, 2])))
CROSSREFS
KEYWORD
nonn
AUTHOR
Rémy Sigrist, Dec 30 2017
STATUS
approved