A340007 - OEIS

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A340007

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

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

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OFFSET

1,18

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.

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) ~ 0.7*A000040(n)/log(log(A000040(n))).

EXAMPLE

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

Cf. A000040, A002110, A038711, A060270, A340006.