id:A048676 - OEIS Search Results

Search: id:A048676

Displaying 1-1 of 1 results found.

page 1

Binary encoding of factorizations, alternative 2, a(n) = bef2(n);.

+0
2

0, 1, 2, 2, 4, 3, 8, 4, 4, 5, 16, 4, 32, 9, 6, 8, 64, 5, 128, 6, 10, 17, 256, 6, 8, 33, 8, 10, 512, 7, 1024, 16, 18, 65, 12, 6, 2048, 129, 34, 8, 4096, 11, 8192, 18, 8, 257, 16384, 10, 16, 9, 66, 34, 32768, 9, 20, 12, 130, 513, 65536, 8, 131072, 1025, 12, 32, 36, 19 (list; graph; listen)

	OFFSET	`1,3`
	COMMENT	`Gives same values as A048675 if the source sequence is square-free (A048672), or there are max two prime divisors or one p with max exponent being 2 (A048623 and A048639).`
	FORMULA	`a(1) = 0, a(n) = 1/4 * (2^(i1+e1) + 2^(i2+e2) + ... + 2^(iz+ez)) if n = p_i1^e1p_i2^e2...*p_iz^ez, where p_i isi-th prime. (e.g. p1=2, p2=3)`
	MAPLE	`bef2 := proc(n) local s, d; s := 0; for d in ifactors(n)[ 2 ] do s := s + (2^(nthprime(d[ 1 ])+d[ 2 ]-2)); od; RETURN(s); end; # for nthprime see A048675`
	CROSSREFS	`Cf. A048675.` `Sequence in context: A163227 A048675 A162474 this_sequence A049287 A006799 A056429` `Adjacent sequences: A048673 A048674 A048675 this_sequence A048677 A048678 A048679`
	KEYWORD	`nonn`
	AUTHOR	`Antti Karttunen, Jul 14 1999`

page 1

Search completed in 0.002 seconds

Last modified December 15 00:47 EST 2009. Contains 170825 sequences.

AT&T Labs Research