Original entry on oeis.org
1, 5, 7, 13, 25, 27, 29, 31, 35, 41, 47, 53, 65, 73, 77, 103, 113, 119, 149, 179, 181, 215, 233, 235, 251, 319, 413, 425, 433, 455, 473, 485, 491, 529, 535, 557, 659, 725
Offset: 1
a(1) = 1 = A378898(1), as (1+1)^2 + 1^2 = 5 is prime.
a(2) = 5 = A378898(3), as (5+3)^2 + 3^2 = 73 is prime, is the first value of A378898 greater than 1.
a(3) = 7 = A378898(13), as (7+13)^2 + 13^2 = 569 is prime, is the first value of A378898 greater than 5.
-
f:= proc(k) local m;
for m from 1 by 2 do
if igcd(m,k) = 1 and isprime((k+m)^2 + k^2) then return m fi
od
end proc:
R:= NULL: count:= 0: rec:= 0:
for k from 1 while count < 30 do
v:= f(k);
if v > rec then
count:= count+1;
R:= R, v;
rec:= v;
fi
od:
R;
Original entry on oeis.org
1, 3, 13, 31, 49, 68, 216, 227, 288, 339, 408, 421, 797, 1176, 1494, 1947, 3876, 6453, 12108, 12558, 13272, 24027, 80667, 92472, 98154, 186543, 765351, 2294838, 6815886, 11105034, 12608001, 13669797, 25343472, 25485726, 40937853, 48562668, 72974013, 122175969
Offset: 1
a(1) = 1, as A378898(1) = 1, with (1+1)^2 + 1^2 = 5 prime.
a(2) = 3, as A378898(3) = 5, with (5+3)^2 + 3^2 = 73 prime, and 3 is the first k with A378898(k) > 1.
a(3) = 13, as A378898(13) = 7, with (7+13)^2 + 13^2 = 569 prime, and 13 is the first k with A378898(k) > 5.
-
f:= proc(k) local m;
for m from 1 by 2 do
if igcd(m,k) = 1 and isprime((k+m)^2 + k^2) then return m fi
od
end proc:
J:= NULL: count:= 0: rec:= 0:
for k from 1 while count < 30 do
v:= f(k);
if v > rec then
count:= count+1;
J:= J, k;
rec:= v;
fi
od:
J;
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