A239619 Base 3 sum of digits of prime(n).

2, 1, 3, 3, 3, 3, 5, 3, 5, 3, 3, 3, 5, 5, 5, 7, 5, 5, 5, 7, 5, 7, 3, 5, 5, 5, 5, 7, 3, 5, 5, 7, 5, 5, 7, 7, 7, 3, 5, 5, 7, 5, 5, 5, 7, 5, 7, 7, 7, 7, 9, 9, 9, 5, 5, 5, 7, 3, 5, 5, 5, 7, 5, 7, 7, 7, 5, 5, 7, 7, 5, 7, 7, 7, 5, 7, 7, 7, 9, 5, 7, 7, 9, 5, 7, 7, 9

Offset

1,1

Links

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

Formula

a(n) = A053735(A000040(n)).

Example

The fifth prime is 11, 11 in base 3 is (1,0,2) so a(5)=1+0+2=3.

Mathematica

Table[Plus @@ IntegerDigits[Prime[n], 3], {n, 1, 100}] (* Vincenzo Librandi, Mar 25 2014 *)

Prog

(Sage) [sum(i.digits(base=3)) for i in primes_first_n(200)]
(Magma) [&+Intseq(NthPrime(n), 3): n in [1..100]]; // Vincenzo Librandi, Mar 25 2014
(PARI) a(n) = vecsum(digits(prime(n), 3)); \\ Michel Marcus, Mar 07 2020

Crossrefs

Cf. A007605, A014499, A053735.

Sequence in context: A038565 A344869 A248605 * A085599 A299966 A302395

Adjacent sequences: A239616 A239617 A239618 * A239620 A239621 A239622

Keyword

nonn,base,easy

Author

Tom Edgar, Mar 22 2014

Status

approved