A249867 -id:A249867 - cp's OEIS frontend

A249686 After A084937(n) has been computed, let m = largest term so far in A084937. Then a(n) = number of positive integers < m that are missing from A084937 at this point.

0, 0, 0, 1, 0, 1, 2, 1, 2, 3, 2, 5, 6, 5, 6, 7, 6, 5, 10, 9, 8, 7, 6, 7, 10, 9, 10, 13, 12, 13, 16, 15, 14, 15, 14, 13, 16, 15, 14, 15, 14, 13, 16, 15, 16, 17, 16, 17, 16, 15, 16, 17, 16, 17, 18, 17, 20, 21, 20, 23, 28, 27, 26, 27, 26, 25, 30, 29, 28, 27, 26, 25, 28

Offset: 1

N. J. A. Sloane, Nov 05 2014

nonn

Running count of missing numbers in A084937.
It appears that at any point, the number of missing even numbers from A084937 is always much larger than the number of missing odd numbers. It would be nice to have a more precise statement of this property.
In this regard, it would be helpful to have two further sequences, one giving the number of even missing numbers at each point, the other giving the number of odd missing numbers. These are now A250099, A250100. See also A249777, A249856, A249867.

			After step 7 of A084937, here is what we have:
1 2 3 4 5 6 7 ... n
1 2 3 5 4 7 9 ... A084937(n)
so m = 9, and the missing numbers < 9 are 6 and 8, so a(7) = 2.

N. J. A. Sloane, Table of n, a(n) for n = 1..100000

Cf. A084937, A250099, A250100. See A249777, A249856, A249857, A249858 for another way of looking at this question.

A249868 Number of days between prime dates in a leap year; starting with Feb 2 and ending with Feb 2 in the following year.

Original entry on oeis.org

1, 2, 2, 4, 2, 4, 2, 4, 6, 2, 1, 2, 2, 4, 2, 4, 2, 4, 6, 2, 32, 1, 2, 2, 4, 2, 4, 2, 4, 6, 2, 32, 1, 2, 2, 4, 2, 4, 2, 4, 6, 2, 94, 1, 2, 2, 4, 2, 4, 2, 4, 6, 65

Offset: 1

Wolfdieter Lang, Nov 23 2014

A prime date means that the number of the day of the month and the number for the month are both prime.
The 53 prime dates in a leap year are:
Feb 2, 3, 5, 7, 11, 13, 17, 19, 23, 29
Mar 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31,
May 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31,
Jul 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31,
Nov 2, 3, 5, 7, 11, 13, 17, 19, 23, 29.
There are 53 entries in this sequence because the 65 days between Nov 29 and Feb 2 in the following year have also been taken into account.
In A249867 the entry a(9) = 7 is replaced by 6, 2.

Cf. A249867.

cp's OEIS Frontend

A249686 After A084937(n) has been computed, let m = largest term so far in A084937. Then a(n) = number of positive integers < m that are missing from A084937 at this point.

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