OFFSET
1,1
COMMENTS
Naively, one might have expected these numbers to have some other distinguishing property (primorials, perhaps), but that seems not to be the case.
Except for 3 of the listed terms, a(n)-1 or a(n)+1 has at most 2 prime divisors. The same is true for many of the terms themselves, often of the form 2^k, 3^k, 2^k*3^k' or 2^k*5^k'. (Factorization of the terms: 2, 3, 2^2, 2^3, 3^2, 2^5, 2^2*3^2, 2^6, 3^4, 2^2*5^2, 11^2, 2^4*3^2, 2^2*3*19, 2^8, 2^2*3*5^2, 2^4*5^2, 3^2*7^2, 2^2*3^2*13, 2^5*5^2, ...) - M. F. Hasler, Sep 25 2017
LINKS
Hugo Pfoertner, Table of n, a(n) for n = 1..56
PROG
(PARI) m=-n=1; until(print1(n", "), until(A039654(n++)>m, ); m=A039654(n)) \\ M. F. Hasler, Sep 25 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Sep 22 2017
STATUS
approved