id:A064839 - OEIS Search Results

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List the natural numbers starting a new row only with each new least prime signature (A025487). a(n) is the column position associated with n.

+0
5

1, 1, 2, 1, 3, 1, 4, 1, 2, 2, 5, 1, 6, 3, 4, 1, 7, 2, 8, 3, 5, 6, 9, 1, 3, 7, 2, 4, 10, 1, 11, 1, 8, 9, 10, 1, 12, 11, 12, 2, 13, 2, 14, 5, 6, 13, 15, 1, 4, 7, 14, 8, 16, 3, 15, 4, 16, 17, 17, 1, 18, 18, 9, 1, 19, 3, 19, 10, 20, 4, 20, 1, 21, 21, 11, 12, 22, 5, 22, 2, 2, 23, 23, 2, 24, 25, 26 (list; graph; listen)

	OFFSET	`1,3`
	COMMENT	`Row 2 records the primes (A000040). Rows 3 and 4 record the semiprimes (A001358). Rows 5, 6 and 9 record the 3-almost primes (A014612) etc. A058933 is a similar sequence based on k-almost primes.`
	EXAMPLE	`The list begins as follows:` `1` `2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 ...` `4 9 25 49 ...` `6 10 14 15 21 22 26 33 34 35 38 39 46 51 ...` `8 27 ...` `12 18 20 28 44 45 50 52 ...` `16 ...`
	CROSSREFS	`A000040, A001358, A014612, A025487 and A058933.` `Sequence in context: A028920 A055396 A057499 this_sequence A094741 A029234 A102613` `Adjacent sequences: A064836 A064837 A064838 this_sequence A064840 A064841 A064842`
	KEYWORD	`easy,nice,nonn`
	AUTHOR	`Alford Arnold (Alford1940(AT)AOL.COM), Oct 24 2001`
	EXTENSIONS	`More terms from Naohiro Nomoto (n_nomoto(AT)yabumi.com), Oct 31 2001`

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Last modified December 17 19:39 EST 2009. Contains 170821 sequences.

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