id:A102300 - OEIS Search Results

Search: id:A102300

Displaying 1-1 of 1 results found.

page 1

Number of distinct prime divisors of n where n and n+1 are composite or twin composite numbers.

+0
1

1, 1, 2, 2, 2, 2, 2, 1, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 1, 3, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 2, 3, 2, 2, 2, 2, 2, 3, 1, 2, 2, 2, 1, 1, 2, 3, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 3, 3, 1, 3, 2, 3, 2, 2, 2, 3, 2, 2, 2, 3, 2, 2 (list; graph; listen)

	OFFSET	`1,3`
	EXAMPLE	`For n=8 n+1=9 a twin composite pair. 8=2^3 has 1 distinct divisor, 2.`
	PROGRAM	`(PARI) f2(n) = for(x=1, n, y=composite(x); if(!isprime(y+1), print1(omega(y)", "))) composite(n) =\The n-th composite number. 1 is def as not prime nor composite. { local(c, x); c=1; x=1; while(c <= n, x++; if(!isprime(x), c++); ); return(x) }`
	CROSSREFS	`Sequence in context: A037813 A159700 A083534 this_sequence A087010 A098220 A133563` `Adjacent sequences: A102297 A102298 A102299 this_sequence A102301 A102302 A102303`
	KEYWORD	`easy,nonn`
	AUTHOR	`Cino Hilliard (hillcino368(AT)gmail.com), Feb 19 2005`

page 1

Search completed in 0.002 seconds

Last modified November 25 20:09 EST 2009. Contains 167514 sequences.

AT&T Labs Research