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A235050
Squarefree numbers such that none of their prime factors share common 1-bits in the same bit-position of their binary representations.
4
1, 2, 3, 5, 7, 10, 11, 13, 17, 19, 23, 26, 29, 31, 34, 37, 41, 43, 47, 53, 58, 59, 61, 67, 71, 73, 74, 79, 82, 83, 89, 97, 101, 103, 106, 107, 109, 113, 122, 127, 131, 137, 139, 146, 149, 151, 157, 163, 167, 173, 178, 179, 181, 191, 193, 194, 197, 199, 202, 211, 218, 223, 226, 227, 229, 233, 239, 241, 251, 257
OFFSET
1,2
COMMENTS
a(1)=1 is included on the grounds that it has no prime factors at all, thus no conflicting 1-bits.
After a(1)=1 all n such that A001414(n) = A072593(n), or equally, A001414(n) = A072594(n).
Union of noncomposites (A008578) and semiprimes of the form 2*A002144 (cf. also A235490).
LINKS
PROG
(Scheme, with Antti Karttunen's IntSeq-library)
(define A235050 (MATCHING-POS 1 1 (lambda (n) (or (= 1 n) (= (A001414 n) (A072593 n))))))
CROSSREFS
Subsequences: A000040, A235490.
Subsequence of A005117.
Sequence in context: A187711 A064627 A324813 * A117286 A169802 A194948
KEYWORD
nonn,easy
AUTHOR
Antti Karttunen, Jan 22 2014
STATUS
approved