A239691 Base 5 sum of digits of prime(n).

2, 3, 1, 3, 3, 5, 5, 7, 7, 5, 3, 5, 5, 7, 7, 5, 7, 5, 7, 7, 9, 7, 7, 9, 9, 5, 7, 7, 9, 9, 3, 3, 5, 7, 9, 3, 5, 7, 7, 9, 7, 5, 7, 9, 9, 11, 7, 11, 7, 9, 9, 11, 9, 3, 5, 7, 9, 7, 5, 5, 7, 9, 7, 7, 9, 9, 7, 9, 11, 13, 9, 11, 11, 13, 7, 7, 9, 9, 5, 9, 11, 9, 7, 9

Offset

1,1

Comments

a(n) is the rank of prime(n) in the base-5 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) = A053824(A000040(n)).

Example

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

Mathematica

Table[Plus @@ IntegerDigits[Prime[n], 5], {n, 1, 100}] (* Vincenzo Librandi, Mar 25 2014 *)

Prog

(Sage) [sum(i.digits(base=5)) for i in primes_first_n(200)]
(Magma) [&+Intseq(NthPrime(n), 5): n in [1..100]]; // Vincenzo Librandi, Mar 25 2014
(PARI) a(n) = sumdigits(prime(n), 5); \\ Michel Marcus, Mar 04 2023

Crossrefs

Cf. A007605, A014499, A053824, A239690.

Sequence in context: A045831 A338988 A046821 * A265496 A238793 A240677

Adjacent sequences: A239688 A239689 A239690 * A239692 A239693 A239694

Keyword

nonn,base

Author

Tom Edgar, Mar 24 2014

Status

approved