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 A193238 Number of prime digits in decimal representation of n. 16
 0, 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 0, 1, 1, 2, 2, 1, 2, 1, 2, 1, 1, 1, 1, 2, 2, 1, 2, 1, 2, 1, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 0, 1, 1, 2, 2, 1, 2, 1, 2, 1, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 0, 1, 1, 2, 2, 1, 2, 1, 2, 1, 1, 0, 0, 1, 1, 0, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,23 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 0..10000 FORMULA a(A084984(n))=0; a(A118950(n))>0; a(A092620(n))=1; a(A092624(n))=2; a(A092625(n))=3; a(A046034(n))=A055642(A046034(n)); a(A000040(n)) = A109066(n). From Hieronymus Fischer, May 30 2012: (Start) a(n) = sum_{j=1..m+1} (floor(n/10^j+0.3) + floor(n/10^j+0.5) + floor(n/10^j+0.8) - floor(n/10^j+0.2) - floor(n/10^j+0.4) - floor(n/10^j+0.6)), where m=floor(log_10(n)), n>0. a(10n+k) = a(n) + a(k), 0<=k<10, n>=0. a(n) = a(floor(n/10)) + a(n mod 10), n>=0. a(n) = sum_{j=0..m} a(floor(n/10^j) mod 10), n>=0. a(A046034(n)) = floor(log_4(3n+1)), n>0. a(A211681(n)) = 1 + floor((n-1)/4), n>0. G.f.: g(x) = (1/(1-x))*sum_{j>=0} (x^(2*10^j) + x^(3*10^j)+ x^(5*10^j) + x^(7*10^j))*(1-x^10^j)/(1-x^10^(j+1)). Also: g(x) = (1/(1-x))*sum_{j>=0} (x^(2*10^j)- x^(4*10^j)+ x^(5*10^j)- x^(6*10^j)+ x^(7*10^j)- x^(8*10^j))/(1-x^10^(j+1)). (End) PROG (Haskell) a193238 n = length \$ filter (`elem` "2357") \$ show n (PARI) a(n)=n=eval(Vec(Str(n))); sum(i=1, #n, isprime(n[i])) \\ Charles R Greathouse IV, Jul 29 2011 CROSSREFS Cf. A010051. Cf. A211681, A046034, A052382, A055640, A055641, A055642, A102669 - A102685, A122640, A117804, A196563, A196564. Sequence in context: A138328 A137264 A289014 * A323826 A275824 A324869 Adjacent sequences:  A193235 A193236 A193237 * A193239 A193240 A193241 KEYWORD nonn,base AUTHOR Reinhard Zumkeller, Jul 19 2011 STATUS approved

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Last modified August 11 23:45 EDT 2020. Contains 336434 sequences. (Running on oeis4.)