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A118469 revision #5

A118469

Triangle read by rows: a(n,m) = If(n = 1, then 1, else Prime(n) - 1 + Sum_{k=n..m} (Prime(k + 1) - Prime(k))/2 ).

1, 1, 3, 1, 4, 5, 1, 6, 7, 8, 1, 7, 8, 9, 11, 1, 9, 10, 11, 13, 14, 1, 10, 11, 12, 14, 15, 17, 1, 12, 13, 14, 16, 17, 19, 20, 1, 15, 16, 17, 19, 20, 22, 23, 25, 1, 16, 17, 18, 20, 21, 23, 24, 26, 29, 1, 19, 20, 21, 23, 24, 26, 27, 29, 32, 33, 1, 21, 22, 23, 25, 26, 28, 29, 31, 34, 35

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

1,3

COMMENTS

An improved triangular Goldbach sequence in which the gap sum is taken from a start at n.

LINKS

Table of n, a(n) for n=1..77.

EXAMPLE

1, 3

1, 4, 5

1, 6, 7, 8

1, 7, 8, 9, 11