1,2

There are no other terms < 2^24. - Jud McCranie, Feb 12 2003

From Amiram Eldar, Aug 22 2020: (Start)

a(9) > 2^31.

The corresponding exponents of 2 are 0, 1, 2, 3, 4, 13, 24, 26, ...

The corresponding indices of Ulam numbers are 1, 2, 4, 6, 9, 694, 1241891, 4964116, ... (End)

Table of n, a(n) for n=1..8.

Index to divisibility sequences

Intersection of A000079 and A002858.

Sequence in context: A281291 A346644 A164312 * A090804 A342773 A080281

Adjacent sequences: A068803 A068804 A068805 * A068807 A068808 A068809

nonn,more

Naohiro Nomoto, Mar 29 2002

a(7)-a(8) from Amiram Eldar, Aug 22 2020

approved