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A254649
a(1) = A007376(1) = 1, n > 1: a(n) = smallest number not occurring earlier, that is the sum of unused next consecutive terms of A007376.
3
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 15, 19, 14, 13, 17, 12, 16, 18, 20, 21, 22, 26, 25, 31, 30, 28, 27, 36, 33, 43, 24, 39, 29, 32, 34, 35, 23, 45, 41, 40, 37, 44, 46, 38, 47, 48, 51, 52, 50, 57, 58, 42, 59, 55, 53, 60, 49, 56, 54, 61, 63, 65, 62, 64, 66, 72
OFFSET
1,2
COMMENTS
A permutation of the positive integers with inverse A254650.
EXAMPLE
. n |1|2|3|4|5|6|7|8|9|10 |11 |12 |13 |14
. a(n) |1|2|3|4|5|6|7|8|9| 10 | 11 | 15 | 19 | 14
--------+-+-+-+-+-+-+-+-+-+---------------+-------+-------+-------+--------
A007376 |1|2|3|4|5|6|7|8|9|1+0+1+1+1+2+1+3|1+4+1+5|1+6+1+7|1+8+1+9|2+0+2....
-
PROG
(Haskell)
a254649 n = a254649_list !! (n-1)
a254649_list = f a007376_list [0] where
f (x:xs) ys = g x xs where
g y zs'@(z:zs) | y `elem` ys = g (y + z) zs
| otherwise = y : f zs' (y:ys)
CROSSREFS
Cf. A007376, A033307, A254650 (inverse), A254656 (fixed points).
Sequence in context: A299441 A069751 A198323 * A261293 A177872 A271839
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Feb 04 2015
STATUS
approved