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A309899 Numbers k = 1, 2, 3, ... are added to the sequence along with k blanks. Next, the numbers k + 1 are inserted on the blanks along with k + 1 blanks. This process is then repeated. 1
1, 2, 2, 3, 4, 3, 3, 5, 6, 4, 4, 4, 7, 8, 5, 5, 9, 5, 5, 10, 6, 6, 11, 12, 6, 6, 6, 7, 7, 13, 14, 8, 7, 7, 15, 8, 7, 7, 16, 9, 17, 8, 8, 18, 9, 10, 8, 8, 8, 19, 20, 9, 9, 11, 10, 21, 22, 9, 9, 12, 9, 9, 10, 10, 23, 11, 24, 13, 25, 10, 10, 11, 26 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Jan Koornstra, Table of n, a(n) for n = 1..10000

EXAMPLE

The first elements are:

  1 _ 2 _ _ 3 _ _ _ 4 _ _ _ _ 5 _ _ _ _ _

    2   _ _   3 _ _   _ 4 _ _   _ _ 5 _ _

        3 _     _ _   4   _ _   _ _   5 _

          4     _ _       _ _   5 _     _

                5 _       _ _     _     _

                  .

  1 2 2 3 4 3 3 5 6 4 4 4 7 8 5 5 9 5 5 10

PROG

(Python)

seq = []

for n in range(1, 100): seq += [n] + n*[-1]

for n in range(2, len(seq)):

  value = n

  gaps = 0

  position = n - 1

  while position < len(seq):

    if seq[position] == -1:

      if gaps > 0: gaps -= 1

      else:

        seq[position] = value

        gaps = value

        value += 1

    position += 1

print(seq)

CROSSREFS

Cf. A309898, A003602, A002260, A306470.

Sequence in context: A048206 A290740 A075765 * A181024 A214744 A014656

Adjacent sequences:  A309896 A309897 A309898 * A309900 A309901 A309902

KEYWORD

nonn,easy

AUTHOR

Jan Koornstra, Aug 21 2019

STATUS

approved

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Last modified August 2 18:52 EDT 2021. Contains 346428 sequences. (Running on oeis4.)