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A344780
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Semiprimes that are product of two distinct Honaker primes.
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0
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34453, 59867, 120191, 136109, 137419, 142921, 170431, 178291, 187723, 205801, 250603, 253223, 273257, 275887, 280471, 286933, 290951, 297763, 319771, 339421, 342163, 348853, 354617, 356189, 357499, 357943, 367193, 376879, 401777, 410947, 413173, 422999, 449723
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OFFSET
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1,1
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COMMENTS
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a(1) = 34453 is the only number <= 5*10^6 that is a triangular number.
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LINKS
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EXAMPLE
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34453 = 131*263 which are distinct Honaker primes.
120191 = 263*457 which are distinct Honaker primes.
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MAPLE
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isA006881 := proc(n)
if numtheory[bigomega](n) =2 and A001221(n) = 2 then
true ;
else
false ;
end if;
end proc:
isA344780 := proc(n)
if isA006881(n) then
for p in ifactors(n)[2] do
if not isA033548(op(1, p)) then
return false;
end if;
end do:
true ;
else
false;
end if;
end proc:
for n from 1 do
if isA344780(n) then
printf("%d, \n", n);
end if;
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MATHEMATICA
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fHQ[n_] := Plus @@ IntegerDigits@n == Plus @@ IntegerDigits@PrimePi@n;
lst = {}; Do[If[Plus @@ Last /@ FactorInteger[n] == 2, a = Length[First /@ FactorInteger[n]]; If[a == 2, b = First /@ FactorInteger[n]; c = b[[1]]; d = b[[2]]; If[fHQ[c] && fHQ[d], AppendTo[lst, {n, c, d}]]]], {n, 2000000}]; lst
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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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STATUS
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approved
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