id:A137661 - OEIS Search Results

Search: id:A137661

Displaying 1-1 of 1 results found.

page 1

a(n+1) = if a(n) is prime then (number of primes so far) else (number of nonprimes so far), a(1) = 1.

+0
2

1, 1, 2, 1, 3, 2, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 10, 11, 9, 12, 13, 10, 14, 15, 16, 17, 11, 12, 18, 19, 13, 14, 20, 21, 22, 23, 15, 24, 25, 26, 27, 28, 29, 16, 30, 31, 17, 18, 32, 33, 34, 35, 36, 37, 19, 20, 38, 39, 40, 41, 21, 42, 43, 22, 44, 45, 46, 47, 23, 24, 48, 49, 50, 51 (list; graph; listen)

	OFFSET	`1,3`
	COMMENT	`All terms greater than 1 occur exactly twice: a(A137662(n)) = a(n).`
	LINKS	`R. Zumkeller, Table of n, a(n) for n = 1..10000`
	FORMULA	`a(n+1) = A005171(a(n))Sum(A005171(a(k)):1<=k<=n) + A010051(a(n))Sum(A010051(a(k)):1<=k<=n).`
	CROSSREFS	`Adjacent sequences: A137658 A137659 A137660 this_sequence A137662 A137663 A137664` `Sequence in context: A133926 A143929 A029163 this_sequence A122545 A072515 A118010`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 04 2008`

page 1

Search completed in 0.002 seconds

Last modified October 11 13:47 EDT 2008. Contains 144830 sequences.

AT&T Labs Research