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A289619 Positions of ones in A289618. 2
6, 10, 14, 15, 21, 22, 26, 30, 33, 34, 35, 36, 38, 39, 42, 46, 51, 55, 57, 58, 62, 65, 66, 69, 70, 72, 74, 77, 78, 82, 85, 86, 87, 91, 93, 94, 95, 96, 100, 102, 105, 106, 108, 110, 111, 114, 115, 118, 119, 122, 123, 129, 130, 133, 134, 138, 141, 142, 143, 145, 146, 154, 155, 158, 159, 160, 161, 165, 166, 170, 174 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Numbers n such that A289617(n) = A005187(A001222(n)) is equal to 1 + A046645(n). Whether a number is included depends only on its prime signature, thus whenever any n is present in the sequence, so is also A046523(n).

LINKS

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

EXAMPLE

6 = 2^1 * 3^1, thus A001222(6) = 1+1 = 2, and A005187(2) = 3. On the other hand, A005187(1) = 1, and 1+1 = 2, which is one less than 3, thus 6 is included like all nonsquare semiprimes.

30 = 2^1 * 3^1 * 5^1, thus A001222(30) = 3, while A005187(3) = 4, thus 30 is included like all products of three distinct primes.

72 = 2^3 * 3^2, thus A001222(72) = 3+2 = 5, and A005187(5) = 8. On the other hand, A005187(3)+A005187(2) = 4+3 = 7, and 8 = 7+1, thus 72 is included in the sequence.

PROG

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

(define A289619 (MATCHING-POS 1 1 (lambda (n) (= 1 (A289618 n)))))

CROSSREFS

Cf. A001222, A005187, A046523, A046645, A289617, A289618.

Differs from A182853 for the first time at n=26, where a(26) = 72, while A182853(26) = 74.

Sequence in context: A279458 A119899 A130092 * A182853 A212168 A080365

Adjacent sequences:  A289616 A289617 A289618 * A289620 A289621 A289622

KEYWORD

nonn

AUTHOR

Antti Karttunen, Jul 08 2017

STATUS

approved

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Last modified September 19 23:31 EDT 2019. Contains 327207 sequences. (Running on oeis4.)