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

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.

Mathematica

Table[Plus @@ IntegerDigits[Prime[n], 7], {n, 1, 100}] (* Vincenzo Librandi, Mar 25 2014 *)

Prog

(Sage) [sum(i.digits(base=7)) for i in primes_first_n(200)]
(Magma) [&+Intseq(NthPrime(n), 7): n in [1..100]]; // Vincenzo Librandi, Mar 25 2014
(PARI) a(n) = sumdigits(prime(n), 7); \\ Michel Marcus, Mar 04 2023

Crossrefs

Cf. A007605, A014499, A053828, A239690, A239691, A239692.

Sequence in context: A123217 A039704 A002752 * A256655 A128047 A105870

Adjacent sequences: A239690 A239691 A239692 * A239694 A239695 A239696

Keyword

nonn,base

Author

Tom Edgar, Mar 24 2014

Status

approved