This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A213368 Row sums of triangle A212954 of two color Ramsey numbers. 1
 1, 2, 4, 8, 16, 30, 60, 102 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The next terms is known to be in the range 179-195. LINKS Eric Weisstein's World of Mathematics, Ramsey Number Wikipedia, Ramsey's theorem EXAMPLE Since the triangle A212954 is symmetric we can write: a(1)  = 1. a(2)  = 2*1 = 2. a(3)  = 2*1+2 = 2+2 = 4. a(4)  = 2*(1+3) = 2*4 = 8. a(5)  = 2*(1+4)+6 = 2*5+6 = 10+6 = 16. a(6)  = 2*(1+5+9) = 2*15 = 30. a(7)  = 2*(1+6+14)+18 = 2*21+18 = 42+18 = 60. a(8)  = 2*(1+7+18+25) = 2*51 = 102. And for the next three known terms we can write: a(9)  = 2*(1+8+23+ ?)+ ? = ?. a(10) = 2*(1+9+28+ ?+ ?) = ?. a(11) = 2*(1+10+36+ ?+ ?)+ ? = ?. CROSSREFS Cf. A000791, A059442, A212954. Sequence in context: A164178 A027423 A140410 * A216212 A164263 A283836 Adjacent sequences:  A213365 A213366 A213367 * A213369 A213370 A213371 KEYWORD nonn,hard,more AUTHOR Omar E. Pol, Jun 10 2012 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 8 01:54 EST 2019. Contains 329850 sequences. (Running on oeis4.)