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%I #16 Jun 14 2022 08:21:20
%S 0,2,4,6,9,11,15,18,22,4,8,11,15,19,24,29,32,37,42,12,18,23,30,34,40,
%T 46,53,59,66,24,30,37,45,51,59,66,73,80,91,37,46,54,62,70,79,88,97,
%U 105,115,53,62,72,82,92,101,112,124,133,143,72,82,94,103
%N a(n) = PrimePi(n*SumOfDigits(n)).
%F a(n) = A000720(A057147(n)).
%e Consider number 2: The sum of digits of 2 equals 2; 2*2 = 4; The number of primes not exceeding 4 is 2. Thus a(2) = 2.
%e Consider number 11: 11*SOD(11) = 22; PrimePi(22) = 8. Thus, a(11) = 8.
%t Table[PrimePi[n Total[IntegerDigits[n]]], {n, 100}]
%o (Python)
%o from sympy import primepi
%o def a(n): return primepi(n*sum(map(int, str(n))))
%o print([a(n) for n in range(1, 65)]) # _Michael S. Branicky_, Apr 25 2022
%o (PARI) a(n) = primepi(n*sumdigits(n)); \\ _Michel Marcus_, Apr 25 2022
%Y Cf. A000720, A007953, A057147, A353126.
%K nonn,base
%O 1,2
%A _Tanya Khovanova_, Apr 25 2022
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