A239693 - OEIS

A239693

Base 7 sum of digits of prime(n).

2, 3, 5, 1, 5, 7, 5, 7, 5, 5, 7, 7, 11, 7, 11, 5, 5, 7, 7, 5, 7, 7, 11, 11, 13, 5, 7, 5, 7, 5, 7, 11, 11, 13, 5, 7, 7, 7, 11, 11, 11, 13, 11, 13, 5, 7, 7, 13, 11, 13, 11, 11, 13, 11, 11, 11, 11, 13, 13, 11, 13, 17, 13, 11, 13, 11, 13, 13, 5, 7, 5, 5, 7, 7

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OFFSET

1,1

COMMENTS

a(n) is the rank of prime(n) in the base-7 dominance order on the natural numbers.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..10000

Tyler Ball and Daniel Juda, Dominance over N, Rose-Hulman Undergraduate Mathematics Journal, Vol. 13, No. 2, Fall 2013.

FORMULA

a(n) = A053828(A000040(n)).

EXAMPLE

The fifth prime is 11, 11 in base 7 is (1,4) so a(5)=1+4=5.