A110978 Odd integers that are nonprime, such that there exist two factors of each number that when multiplied together in binary base, do not ever require the use of a "carry" bit.

15, 27, 45, 51, 63, 85, 95, 99, 111, 119, 123, 125, 153, 165, 175, 187, 189, 195, 207, 219, 221, 231, 243, 245, 255, 297, 315, 325, 335, 363, 365, 387, 399, 411, 429, 435, 441, 447, 455, 483, 485, 495, 507, 511, 561, 585, 603, 621, 627, 629, 639, 645, 655

Offset

0,1

Links

Table of n, a(n) for n=0..52.

Example

45 = 5*9:
....1001.(9)
...*.101.(times.5)
.-------
....1001
...00000
..100100
.-------
..101101.(=45)
No carry bit needed!

Crossrefs

Sequence in context: A096022 A097222 A004069 * A274433 A227804 A365451

Adjacent sequences: A110975 A110976 A110977 * A110979 A110980 A110981

Keyword

base,easy,nonn

Author

Paul Klemstine (paulklemstine(AT)yahoo.com), Sep 29 2005

Status

approved