A373262 - OEIS

A373262

Numbers k for which A276085(k) == -1 (mod 3), where A276085 is the primorial base log-function.

3, 4, 15, 18, 20, 21, 24, 28, 32, 33, 39, 44, 51, 52, 57, 68, 69, 75, 76, 81, 87, 90, 92, 93, 100, 105, 108, 111, 116, 120, 123, 124, 126, 129, 140, 141, 144, 147, 148, 159, 160, 164, 165, 168, 172, 177, 183, 188, 192, 195, 196, 198, 201, 212, 213, 219, 220, 224, 231, 234, 236, 237, 244, 249, 255, 256, 260, 264, 267

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OFFSET

1,1

COMMENTS

Numbers k such that the 2-adic valuation of k minus the 3-adic valuation of k is equal to -1 modulo 3.

When terms are multiplied by 2, forms a subsequence of A339746 (its even terms), and when multiplied by 3, forms a subsequence of A373261 (its multiples of 3).

More widely stated, the sequence lists one part of a 3-part partition of the positive integers with a symmetric relationship between the parts (further explained in the 2021 comment in A339746). - Peter Munn, Jul 19 2024

LINKS

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

FORMULA

{k such that A007814(k)-A007949(k) == -1 (mod 3)}.

PROG

(PARI) isA373262 = A373263;

CROSSREFS

Cf. A007814, A007949, A276085, A373263 (characteristic function).

Positions of -1's in A373153.

The positive integers are partitioned between A339746, A373261, and this sequence.

Sequence in context: A285475 A341779 A136641 * A325186 A053359 A056742

Adjacent sequences: A373259 A373260 A373261 * A373263 A373264 A373265

KEYWORD

nonn

AUTHOR

Antti Karttunen, May 30 2024

STATUS

approved