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A113590
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Least multiple of prime(n) containing only prime digits (2,3,5,7).
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2
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2, 3, 5, 7, 22, 52, 255, 57, 23, 232, 372, 37, 533, 2322, 235, 53, 2537, 732, 335, 355, 73, 237, 332, 2225, 2522, 2222, 2575, 535, 327, 2373, 22225, 2227, 7535, 3753, 2235, 755, 2355, 7335, 27555, 23355, 537, 2353, 573, 772, 27777, 5373, 2532, 223, 227, 5725, 233
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OFFSET
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1,1
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COMMENTS
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a(n) = prime(n) if prime(n) is in A019546.
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LINKS
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MAPLE
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N:= 100: # to get a(1)..a(N)
pn:= ithprime(N):
count:= 0:
digs:= [2, 3, 5, 7]:
for d from 1 while count < N do
for m from 4^d to 2*4^d-1 while count < N do
L:= convert(m, base, 4);
n:= add(digs[L[i]+1]*10^(i-1), i=1..nops(L)-1);
ps:= select(p -> p <= pn and not assigned(A[p]), numtheory:-factorset(n));
count:= count + nops(ps);
for p in ps do A[p]:= n od:
od od:
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CROSSREFS
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KEYWORD
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base,easy,nonn
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AUTHOR
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EXTENSIONS
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More terms from Nick Woods (njw130(AT)psu.edu), Apr 25 2006
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STATUS
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approved
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