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.
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
KEYWORD
nonn,base,less
AUTHOR
Tanya Khovanova, Jun 15 2021
STATUS
approved