A382722 Number of entries in the n-th row of Pascal's triangle not divisible by 13.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, 72, 78, 7, 14, 21

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

Hsien-Kuei Hwang, Svante Janson, and Tsung-Hsi Tsai, Periodic minimum in the count of binomial coefficients not divisible by a prime, arXiv:2408.06817 [math.NT], 2024.

Mathematica

Table[Times@@(IntegerDigits[n, 13]+1), {n, 0, 80}] (* Vincenzo Librandi, Feb 21 2026 *)

Prog

(Python)
from math import prod
from gmpy2 import digits
def A382722(n): return prod(int(d, 13)+1 for d in digits(n, 13)) # Chai Wah Wu, Aug 10 2025
(Magma) [&*[ d+1 : d in (n eq 0 select [0] else IntegerToSequence(n, 13))] : n in [0..80]]; // Vincenzo Librandi, Feb 21 2026

Crossrefs

Cf. A001316, A006047, A194459, A382720-A382721.

Sequence in context: A053834 A297245 A043273 * A268982 A278065 A373233

Adjacent sequences: A382719 A382720 A382721 * A382723 A382724 A382725

Keyword

nonn

Author

N. J. A. Sloane, Apr 23 2025

Status

approved