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A187098
A permutation of the natural numbers related to Goldbach conjecture.
4
1, 2, 3, 4, 5, 6, 7, 9, 8, 11, 10, 13, 14, 12, 15, 17, 18, 16, 19, 21, 20, 23, 24, 25, 22, 27, 26, 29, 30, 28, 31, 33, 32, 35, 36, 39, 38, 42, 37, 34, 40, 43, 45, 41, 44, 48, 49, 46, 51, 47, 50, 53, 56, 57, 52, 55, 54, 60, 58, 63, 59, 65, 62, 66, 61, 70, 67, 69, 68, 71, 72, 73, 75, 74, 77, 78, 76, 81, 80, 84
OFFSET
1,2
COMMENTS
a(n) = if n <= 2 then n else A187085(n-2)/2;
for n > 2: a(n+1) = a(n) + (A187072(n) - A187072(n-2)) / 2.
PROG
(Haskell)
a187098 n = a187098_list !! (n-1)
a187098_list = 1 : 2 : map (`div` 2) a187085_list
CROSSREFS
Cf. A065306, A187099 (inverse).
Sequence in context: A284120 A183081 A140595 * A187099 A284049 A063932
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Mar 04 2011
STATUS
approved