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A328915
If n = Product (p_j^k_j) then a(n) = Product (nextprime(p_j)), where nextprime = A151800.
1
1, 3, 5, 3, 7, 15, 11, 3, 5, 21, 13, 15, 17, 33, 35, 3, 19, 15, 23, 21, 55, 39, 29, 15, 7, 51, 5, 33, 31, 105, 37, 3, 65, 57, 77, 15, 41, 69, 85, 21, 43, 165, 47, 39, 35, 87, 53, 15, 11, 21, 95, 51, 59, 15, 91, 33, 115, 93, 61, 105, 67, 111, 55, 3, 119, 195, 71, 57, 145, 231
OFFSET
1,2
COMMENTS
All terms are odd.
FORMULA
If n = Product (p_j^k_j) then a(n) = Product (prime(pi(p_j) + 1)), where pi = A000720.
a(n) = A007947(A003961(n)).
EXAMPLE
a(12) = a(2^2 * 3) = a(prime(1)^2 * prime(2)) = prime(2) * prime(3) = 3 * 5 = 15.
MAPLE
a:= n-> mul(nextprime(i[1]), i=ifactors(n)[2]):
seq(a(n), n=1..100); # Alois P. Heinz, Oct 30 2019
MATHEMATICA
a[1] = 1; a[n_] := Times @@ (NextPrime[#[[1]]] & /@ FactorInteger[n]); Table[a[n], {n, 1, 70}]
PROG
(PARI) a(n) = my(f=factor(n)); prod(k=1, #f~, nextprime(f[k, 1]+1)); \\ Michel Marcus, Oct 30 2019
KEYWORD
nonn,mult
AUTHOR
Ilya Gutkovskiy, Oct 30 2019
STATUS
approved