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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: 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

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