cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A339274 Number of times the n-th prime (=A000040(n)) occurs in A033933.

Original entry on oeis.org

0, 0, 0, 1, 1, 2, 0, 0, 1, 0, 4, 1, 1, 1, 1, 2, 3, 2, 1, 2, 3, 2, 2, 2, 3, 3, 4, 0, 4, 2, 4, 2, 1, 1, 1, 1, 2, 2, 2, 1, 1, 0, 3, 3, 3, 2, 2, 1, 0, 4, 1, 2, 0, 2, 1, 3, 2, 4, 2, 2, 3, 4, 0, 4, 1, 3, 2, 2, 4, 0, 5, 2, 6, 2, 3, 3, 0, 5, 2, 4, 2, 3, 3, 1, 3, 2
Offset: 1

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Author

A.H.M. Smeets, Dec 25 2020

Keywords

Comments

Each term in A033933 is either 1 or a prime number. Moreover it is known that each prime occurs only a finite number of times in A033933.
By excluding the terms that equal one from A033933, we observe the smallest value of A033933(n)/log(n!) in the range n = 3..2000 to be ~0.1552. From this it is believed that the primes less than 0.9*log(2001!)*0.1552 (~ 1846) will not occur anymore in the sequence A033933 for n > 2000; the applied factor 0.9 is a safety factor to be more or less sure that the prime numbers up to about 1846 will no longer occur in A033933.

Examples

			The prime number 13 occurs 2 times in A033933, and A000040(6) = 13, so a(6) = 2.
		

Crossrefs

See also A340006, A340007 (p#).

Formula

It seems that Sum_{k = 1..n} a(k) ~ 0.7*A000040(n)/log(log(A000040(n))).

A340007 Number of times the n-th prime (=A000040(n)) occurs in A038711.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 0, 1, 3, 0, 1, 0, 1, 0, 1, 0, 1, 2, 1, 1, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 2, 0, 1, 2, 0, 2, 0, 1, 2, 2, 0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1, 1, 2, 0, 4, 0, 0, 0, 1, 0, 0, 1, 1, 2, 0, 1, 1, 0, 1, 2, 0, 0, 2, 1
Offset: 1

Views

Author

A.H.M. Smeets, Dec 26 2020

Keywords

Comments

Each term in A038711 is either 1 or a prime number. Moreover it is known that each prime occurs only a finite number of times in A038711.
By excluding the terms that equal one from A038711, we observe the smallest value of A038711(n)/log(A002110(n)) in the range n = 2..1000 to be ~1.017. From this it is believed that the primes less than 0.9*log(A002110(1001))*1.017 (~ 7157) will not occur anymore in the sequence A038711 for n > 1000; the applied factor 0.9 is a safety factor to be more or less sure that the prime numbers up to about 7157 will no longer occur in A038711.

Examples

			The prime number 17 occurs 1 time in A038711, and A000040(7) = 17, so a(7) = 1.
The prime number 5 does not occur in A038711, and A000040(3) = 5, so a(3) = 0.
		

Crossrefs

Formula

It seems that Sum_{k = 1..n} a(k) ~ 0.7*A000040(n)/log(log(A000040(n))).
Showing 1-2 of 2 results.