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 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 Table of n, a(n) for n=1..8. 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: A335542 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

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Last modified August 9 20:04 EDT 2024. Contains 375044 sequences. (Running on oeis4.)