A391840 Base 16 sum of digits of prime(n).

2, 3, 5, 7, 11, 13, 2, 4, 8, 14, 16, 7, 11, 13, 17, 8, 14, 16, 7, 11, 13, 19, 8, 14, 7, 11, 13, 17, 19, 8, 22, 11, 17, 19, 14, 16, 22, 13, 17, 23, 14, 16, 26, 13, 17, 19, 16, 28, 17, 19, 23, 29, 16, 26, 2, 8, 14, 16, 7, 11, 13, 8, 7, 11, 13, 17, 16, 7, 17, 19, 8, 14, 22, 13, 19, 23, 14, 22, 11, 19

Offset

1,1

Links

Table of n, a(n) for n=1..80.

Formula

a(n) = A053836(A000040(n)).

Example

The 13th prime is 41, 41 in base 16 is (2, 9) so a(13) = 2 + 9 = 11.

Mathematica

a[n_] := DigitSum[Prime[n], 16]; Array[a, 100] (* Amiram Eldar, Dec 21 2025 *)

Prog

(PARI) a(n) = sumdigits(prime(n), 16);

Crossrefs

Cf. A007605, A014499, A053836, A239690, A239694.

Sequence in context: A039715 A039714 A039713 * A142713 A039712 A072700

Adjacent sequences: A391837 A391838 A391839 * A391841 A391842 A391843

Keyword

nonn,base

Author

Kaloian Ivanov, Dec 21 2025

Status

approved