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A345351
Triangular numbers such that the sum of cubes of their digits is prime.
0
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.
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
KEYWORD
nonn,base,less
AUTHOR
Tanya Khovanova, Jun 15 2021
STATUS
approved