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A046407
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Odd numbers with exactly 5 distinct palindromic prime factors.
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3
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116655, 151305, 174405, 209055, 220605, 361515, 407715, 430815, 442365, 839685, 874335, 908985, 920535, 1061445, 1072995, 1389255, 1601355, 1919505, 2025555, 2077005, 2183115, 2489655, 2516415, 2627205, 2869755, 3016365, 3028305
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OFFSET
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1,1
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LINKS
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MAPLE
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N:= 10^7; # for terms <= N
PP:= NULL:
for d from 1 to length(N)/2 do
for x from 10^(d-1) to 10^d-1 do
y:= x*10^(d-1) + rev(floor(x/10));
if isprime(y) then PP:= PP, y fi;
od;
if d = 1 then PP:= PP, 11 fi;
od:
PP:= [PP][2..-1]:
Res:= NULL:
for i1 from 1 to nops(PP) do
v1:= PP[i1];
if v1*3*5*7*11 > N then break fi;
for i2 from 1 to i1-1 do
v2:= v1*PP[i2];
if v2*3*5*7 > N then break fi;
for i3 from 1 to i2-1 do
v3:= v2*PP[i3];
if v3 * 3*5 > N then break fi;
for i4 from 1 to i3-1 do
v4:= v3*PP[i4];
if v4* 3 > N then break fi;
for i5 from 1 to i4-1 do
v:= v4*PP[i5];
if v > N then break fi;
Res:= Res, v
od od od od od:
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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