A239695 Base 9 sum of digits of prime(n).

2, 3, 5, 7, 3, 5, 9, 3, 7, 5, 7, 5, 9, 11, 7, 13, 11, 13, 11, 15, 9, 15, 3, 9, 9, 5, 7, 11, 5, 9, 7, 11, 9, 11, 13, 15, 13, 3, 7, 5, 11, 5, 7, 9, 13, 7, 11, 15, 11, 13, 17, 15, 17, 11, 9, 7, 13, 7, 13, 9, 11, 13, 11, 15, 17, 13, 11, 9, 11, 13, 9, 15, 15, 13, 11

Offset

1,1

Comments

a(n) is the rank of prime(n) in the base-9 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) = A053830(A000040(n)).

Example

The fifth prime is 11, 11 in base 9 is (1,2) so a(5)=1+2=3.

Mathematica

Table[Plus @@ IntegerDigits[Prime[n], 9], {n, 1, 100}] (* Vincenzo Librandi, Mar 25 2014 *)

Prog

(Sage) [sum(i.digits(base=9)) for i in primes_first_n(200)]
(Magma) [&+Intseq(NthPrime(n), 9): n in [1..100]]; // Vincenzo Librandi, Mar 25 2014
(PARI) a(n) = sumdigits(prime(n), 9); \\ Michel Marcus, Mar 04 2023

Crossrefs

Cf. A007605, A014499, A053830, A239690, A239691, A239692, A239693, A239694.

Sequence in context: A108534 A039706 A156208 * A073034 A239037 A126050

Adjacent sequences: A239692 A239693 A239694 * A239696 A239697 A239698

Keyword

nonn,base

Author

Tom Edgar, Mar 24 2014

Status

approved