

A277377


Each odd integer k is followed by k even integers.


1



1, 0, 3, 2, 4, 6, 5, 8, 10, 12, 14, 16, 7, 18, 20, 22, 24, 26, 28, 30, 9, 32, 34, 36, 38, 40, 42, 44, 46, 48, 11, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 13, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 15, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 17, 128, 130, 132
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OFFSET

1,3


COMMENTS

The sequence starts with a(1) = 1 and was always extended with the smallest nonnegative integer not yet present that does not lead to a contradiction.
Sequence places odd numbers (2n  1) at position A002061(n). First even number to appear after this is A001105(n  1).  Michael De Vlieger, Oct 12 2016


LINKS

JeanMarc Falcoz, Table of n, a(n) for n = 1..7162


FORMULA

a(m*(m+1) + 1) = 2m + 1 for m > 0.  David A. Corneth, Oct 11 2016


EXAMPLE

As a(1) = 1, we take for a(2) the even integer "0"; we then extend the sequence with a(3) which must be the smallest odd integer not yet present: this is "3"; we take for a(4), a(5) and a(6) the 3 smallest even integers not yet present: they are 2, 4 and 6; we then extend the sequence with the smallest odd available integer, which is a(7) = 5. Etc.


MATHEMATICA

Table[Prepend[2 Range[#^2, #^2 + 2 n  2] &@ (n  1), 2 n  1], {n, 9}] // Flatten (* Michael De Vlieger, Oct 12 2016 *)


CROSSREFS

Cf. A001105, A002061 (Position of odd numbers in a(n)).
Sequence in context: A254108 A093573 A126290 * A227741 A059417 A078824
Adjacent sequences: A277374 A277375 A277376 * A277378 A277379 A277380


KEYWORD

nonn,base


AUTHOR

Eric Angelini and JeanMarc Falcoz, Oct 11 2016


STATUS

approved



