A340006 Number of times the n-th prime (=A000040(n)) occurs in A060270.

0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 2, 0, 1, 3, 1, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 2, 0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 0, 3, 1, 0, 1, 1, 0, 2, 1, 1, 0, 0, 0, 1, 0, 2, 2, 1, 1, 2, 1, 0, 1, 0, 0, 0, 0, 2, 1, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 2

Offset

1,21

Comments

Each term in A060270 is either 1 or a prime number. Moreover it is known that each prime occurs only a finite number of times in A060270.

By excluding the terms that equal one from A060270, we observe the smallest value of A060270(n)/log(A002110(n)) in the range n = 2..1000 to be ~1.014. From this it is believed that the primes less than 0.9*log(A002110(1001))*1.014 (~ 7138) will not occur anymore in the sequence A060270 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 7138 will no longer occur in A060270.

Links

A.H.M. Smeets, Table of n, a(n) for n = 1..916

A.H.M. Smeets, Sum_{k = 1..n} a(k) versus A000040(n)

Formula

It seems that Sum_{k = 1..n} a(k) ~ 0.2*A000040(n)/log(log(A000040(n))).

Example

The prime number 7 does not occur in A060270, and A000040(4) = 7, so a(4) = 0.
The prime number 11 occurs 1 time in A060270, and A000040(5) = 11, so a(5) = 1.

Crossrefs

Cf. A000040, A002110, A038711, A060270, A340007.

See also A339274, A339959 (n!).

Sequence in context: A181940 A356154 A261209 * A093555 A065432 A094184

Adjacent sequences: A340003 A340004 A340005 * A340007 A340008 A340009

Keyword

nonn

Author

A.H.M. Smeets, Dec 26 2020

Status

approved