A287611 Numbers which are twice an Ulam number but not the sum of two distinct Ulam numbers.

2, 94, 96, 194, 204, 678, 712, 2310, 7446

Offset

1,1

Comments

The sequence could also be described as numbers that have no representation as a sum of two distinct Ulam numbers, but have a "pseudo-representation" u + u, where u is an Ulam number.

a(10), if it exists, is larger than 5*10^7. - Giovanni Resta, May 31 2017

Links

Table of n, a(n) for n=1..9.

Formula

a(n) = A285882(n)/2. - Giovanni Resta, May 31 2017

Example

204 is in the sequence since it can't be written as the sum of two distinct Ulam numbers, but 204 = 102 + 102, where 102 is an Ulam number.

Crossrefs

Cf. A002858, A285882.

Sequence in context: A239006 A248627 A290936 * A363017 A158980 A343457

Adjacent sequences: A287608 A287609 A287610 * A287612 A287613 A287614

Keyword

nonn,more

Author

Enrique Navarrete, May 27 2017

Status

approved