OFFSET
1,2
COMMENTS
A055932 lists numbers m whose prime divisors p are consecutive primes starting with 2, while A025487 lists numbers m that are products of primorials. With both, we find a range of indices of primes 1, 2, ..., k that divide m. While A055932 admits any multiplicity for primes regardless of their index, the latter only admits decreasing multiplicities as prime index k increases. Therefore, A025487 is a subset of A055932.
LINKS
Michael De Vlieger, Table of n, a(n) for n = 1..10000
EXAMPLE
a(1) = 1 since the empty product is the first term in both sequences.
a(2) = 2 since 2 is the smallest prime and appears in both sequences after 1.
8 is not in the sequence, since A055932(8) = 18 = 2 * 3^2 and is not the product of primorials (or, rather, we can identify a smaller number - 12 - for the prime signature p^2 * q).
MATHEMATICA
CROSSREFS
KEYWORD
nonn
AUTHOR
Michael De Vlieger, Feb 01 2020
STATUS
approved