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A260730 Numbers n for which A065339(n) > A260728(n). 4
21, 33, 42, 57, 66, 69, 77, 84, 93, 105, 114, 129, 132, 133, 138, 141, 154, 161, 165, 168, 177, 186, 189, 201, 209, 210, 213, 217, 228, 231, 237, 249, 253, 258, 264, 266, 273, 276, 282, 285, 297, 301, 308, 309, 321, 322, 329, 330, 336, 341, 345, 354, 357, 372, 378, 381, 385, 393, 399, 402, 413, 417, 418, 420, 426, 429, 434, 437, 441, 453, 456, 462, 465, 469, 473, 474, 483, 489, 497, 498, 501, 506, 513, 516, 517, 525, 528, 532, 537, 546, 552 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Numbers n such that when the exponents in the prime factorization of A097706(n) are added in base-2 they produce at least one carry-bit. In other words, in that set of exponents {e1, e2, ..., en} there is at least one pair e_i, e_j that their binary representations have at least one 1-bit in the same position. (Here i and j are distinct as e_i and e_j are exponents of different primes, although e_i could be equal to e_j. See the examples.)

This differs from A119973 for the first time at n=30 where a(30)=231, term which is not present in A119973. Note that n=231 is the first position where the difference A065339(n) - A260728(n) > 1 as 231 = 3*7*11, a product of three distinct 4k+3 primes, thus A065339(231) = 3, while A260728(231) = 1.

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

EXAMPLE

21 = 3^1 * 7^1 is present, because in its prime factors of the form 4k+3 (which are 3 and 7) the exponents 1 and 1 have at least one 1-bit in the same position, thus producing a carry-bit when summed in base-2.

63 = 3^2 * 7^1 is NOT present, because in its prime factors of the form 4k+3 the exponents 2 and 1 ("10" and "1" in binary) do NOT produce a carry-bit when summed in base-2, as those binary representations do not have any 1's in a common position.

189 = 3^3 * 7^1 is present, because in its prime factors of the form 4k+3 the exponents 3 and 1 ("11" and "1" in binary) have at least one 1-bit in the same position, thus producing a carry-bit when summed in base-2.

PROG

(Scheme, with Antti Karttunen's IntSeq-library)

(define A260730 (NONZERO-POS 1 1  (lambda (n) (- (A065339 n) (A260728 n)))))

CROSSREFS

Cf. A065339, A260728, A097706, A119973.

Sequence in context: A036382 A298855 A273201 * A119973 A279229 A141249

Adjacent sequences:  A260727 A260728 A260729 * A260731 A260732 A260733

KEYWORD

nonn

AUTHOR

Antti Karttunen, Aug 12 2015

STATUS

approved

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Last modified September 21 21:57 EDT 2019. Contains 327282 sequences. (Running on oeis4.)