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A239693 Base 7 sum of digits of prime(n). 3
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 (list; graph; refs; listen; history; text; internal format)
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

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

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Last modified June 19 15:58 EDT 2021. Contains 345144 sequences. (Running on oeis4.)