Recommend a regular column automatically find the number of sites
Data is large!
Chinese version http://oeis.org/?language=chineseS
Within the website description:
The main purpose OEIS are:
identification sequence
for more terms of sequence, formulas, references, links, and other program
you're trying to solve the problem, but it is too difficult.
Answer the first few cases are 1,1,2,4,9,21,51,127.
Then find this content in OEIS in, and see if anyone had previously encountered this sequence (they have).
Hope this help you!