A345351 Triangular numbers such that the sum of cubes of their digits is prime.

496, 946, 1378, 2485, 7381, 7750, 8128, 10011, 11935, 12880, 13366, 13861, 14365, 15931, 19900, 31375, 33670, 34453, 35245, 36046, 38503, 41905, 43660, 44551, 45451, 46360, 48205, 49141, 50086, 58996, 65341, 66430, 73153, 103285, 104653, 111628, 114481, 124750

Offset

1,1

Comments

The cubes of the digits of 496 are 64, 729, and 216. They sum up to a prime number 1009. Thus, 496 is in the sequence.

Links

Table of n, a(n) for n=1..38.

Mathematica

Select[Table[n (n + 1)/2, {n, 500}], PrimeQ[Total[IntegerDigits[#]^3]] &]

Prog

(Python)
from sympy import isprime
def A000217(n): return n*(n+1)//2
def A055012(n): return sum(int(d)**3 for d in str(n))
def ok(tri): return isprime(A055012(tri))
print(list(filter(ok, (A000217(n) for n in range(500))))) # Michael S. Branicky, Jun 15 2021

Crossrefs

Cf. A000217.

Sequence in context: A214555 A333756 A179170 * A157447 A109477 A302366

Adjacent sequences: A345348 A345349 A345350 * A345352 A345353 A345354

Keyword

nonn,base,less

Author

Tanya Khovanova, Jun 15 2021

Status

approved