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A127367 Inverse permutation to A127366. 2
0, 2, 1, 5, 3, 7, 4, 10, 6, 12, 8, 14, 9, 17, 11, 19, 13, 21, 15, 23, 16, 26, 18, 28, 20, 30, 22, 32, 24, 34, 25, 37, 27, 39, 29, 41, 31, 43, 33, 45, 35, 47, 36, 50, 38, 52, 40, 54, 42, 56, 44, 58, 46, 60, 48, 62, 49, 65, 51, 67, 53, 69, 55, 71, 57, 73, 59, 75, 61, 77, 63, 79, 64 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Let m be the largest number such that n >= m(m+1). If n is even, a(n) = n - m; otherwise a(n) = n + m + 1.

a(A005408(n)) > 0; a(A005843(n)) <= 0. [Reinhard Zumkeller, Oct 12 2011]

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

Index entries for sequences that are permutations of the natural numbers

PROG

(Haskell)

a127367 n | even n    = n - m + 1

          | otherwise = n + m

          where m = length $ takeWhile (<= n) a002378_list

-- Reinhard Zumkeller, Oct 12 2011

CROSSREFS

Cf. A127366, A002378, A000194.

Cf. A002378 (oblong numbers).

Sequence in context: A262211 A094512 A182650 * A054084 A296069 A058683

Adjacent sequences:  A127364 A127365 A127366 * A127368 A127369 A127370

KEYWORD

nonn

AUTHOR

Franklin T. Adams-Watters, Jan 11 2007

STATUS

approved

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Last modified March 8 02:09 EST 2021. Contains 341934 sequences. (Running on oeis4.)