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));
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)
MATHEMATICA
Count[IntegerDigits[#], _?PrimeQ]&/@Range[0, 100] (* Harvey P. Dale, Nov 13 2022 *)
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
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Jul 19 2011
STATUS
approved