OFFSET
1,1
COMMENTS
Conjecture: Composite terms k greater than 25 will have either two or six nontrivial divisors (that is, divisors d with 1 < d < k).
The total numbers of divisors of the first 31 terms are 2, 2, 2, 2, 2, 3, 2, 2, 4, 2, 2, 2, 2, 2, 4, 4, 4, 4, 4, 2, 8, 2, 2, 8, 2, 4, 2, 8, 4, 2, 2. - N. J. A. Sloane, Dec 01 2019
LINKS
Rémy Sigrist and Giovanni Resta, Table of n, a(n) for n = 1..48
Rémy Sigrist, C++ program for A330070
EXAMPLE
a(6) = 25 = 5 * 5: 5 is not in the sequence, and no combination of 2, 3, 7, 11, and 17 sums to 25.
PROG
(C++) See Links section.
CROSSREFS
KEYWORD
nonn
AUTHOR
J. Stauduhar, Nov 30 2019
EXTENSIONS
Terms a(24)-a(31) from Christian Lawson-Perfect, Dec 01 2019
Terms a(32)-a(37) from Rémy Sigrist, Dec 02 2019
STATUS
approved