A046892 Number of permutations of digits of A046891(n) that are primes.
0, 1, 2, 3, 4, 5, 8, 9, 10, 11, 13, 16, 18, 22, 31, 34, 37, 39, 40, 49, 52, 64, 80, 87, 93, 115, 121, 144, 149, 160, 172, 225, 233, 298, 299, 308, 384, 399, 408, 423, 475, 484, 569, 571, 738, 806, 835, 863, 934, 1247, 1413, 1525, 1739, 1775, 2282, 2303, 2325
Offset: 1
Links
- Michael S. Branicky, Table of n, a(n) for n = 1..91
Programs
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Mathematica
a = {}; b = -1; Do[c = Count[ PrimeQ[ FromDigits /@ Permutations[IntegerDigits[n]]], True]; If[c > b, b = c; a = Append[a, c]], {n, 1, 10^8}]; a -
Python
from sympy import prime from gmpy2 import is_prime from sympy.utilities.iterables import multiset_permutations as mp from itertools import count, islice, combinations_with_replacement as mc def f(n): return sum(1 for p in mp(str(n)) if is_prime(t:=int("".join(p)))) def bgen(d): for f in "123456789": yield from map(int, (f+"".join(m) for m in mc("0123456789", d-1))) def agen(): record = -1 for d in count(1): for k in bgen(d): v = f(k) if v > record: record = v yield v print(list(islice(agen(), 30))) # Michael S. Branicky, Feb 17 2024