OFFSET
1,3
COMMENTS
a(A080148(m)) = 0. - Joerg Arndt, Oct 22 2014
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(1)=1 is in this sequence because 1 is in A008578 and the largest prime factor of 1^2+1 = 2 is prime(1).
MAPLE
A249132:= proc(n) local p, i, k, a, b;
p:= ithprime(n);
if p mod 4 = 3 then return 0 fi;
a:= numtheory:-msqrt(-1, p);
if a < p/2 then b:= p-a
else b:= a; a:= p-a
fi;
for i from 0 do
for k in [a+i*p, b+i*p] do
if isprime(k) and p = max(numtheory:-factorset(k^2+1)) then
return(k)
fi
od
od
end proc:
1, seq(A249132(n), n=2..100); # Robert Israel, Nov 10 2014
MATHEMATICA
a249132[n_Integer] := Module[{t = Table[0, {n}], k, s, p}, Do[If[Mod[Prime[k], 4] == 3, t[[k]] = -1], {k, n}]; k = 0; While[Times @@ t == 0, k++; s = FactorInteger[k^2 + 1][[-1, 1]]; p = PrimePi[s]; If[p <= n && t[[p]] == 0 && ! CompositeQ[k], t[[p]] = k]]; t /. -1 -> 0]; a249132[120] (* Michael De Vlieger, Nov 11 2014, adapted from A223702 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Oct 22 2014
STATUS
approved