A059339 A+B=C for 0<=A, 0<=B, A<=B; if n is a C-almost prime then a(n) = number of decompositions of n into sum of an A-almost prime and a B-almost prime.

0, 0, 1, 1, 0, 1, 0, 1, 1, 3, 0, 2, 0, 2, 2, 1, 0, 1, 0, 2, 1, 4, 0, 2, 1, 4, 5, 6, 0, 1, 0, 2, 1, 5, 1, 3, 0, 2, 2, 4, 0, 3, 0, 5, 7, 4, 0, 3, 1, 4, 0, 7, 0, 3, 1, 5, 0, 5, 0, 6, 0, 3, 7, 4, 0, 4, 0, 10, 1, 6, 0, 4, 0, 5, 8, 10, 0, 5, 0, 6, 13, 5, 0, 7, 1, 6, 1, 8, 0, 6, 1, 11, 0, 6, 1, 7, 0, 13, 10, 11, 0

Offset

1,10

Comments

E.g. n=10, 10 is 2-almost prime (semiprime). Therefore C=2. 10=1+9(A=0,B=2); 10=7+3(A=1,B=1); 10=5+5(A=1,B=1), so a(10)=3.

Links

Table of n, a(n) for n=1..101.

Crossrefs

Sequence in context: A161970 A230446 A260737 * A241181 A171772 A092735

Adjacent sequences: A059336 A059337 A059338 * A059340 A059341 A059342

Keyword

easy,nonn

Author

Naohiro Nomoto, Jan 27 2001

Status

approved