



1, 2, 3, 26, 32, 34, 37, 49, 55, 62, 64, 74, 75, 76, 77, 164, 171, 189, 224, 273, 279, 280, 285, 303, 333, 345, 356, 363, 368, 382, 399, 411, 416, 422, 429, 430, 435, 441, 453, 470, 472, 483, 494, 524, 539, 561, 566, 579, 580, 585, 603, 609, 621, 644, 662, 666, 674, 693, 704, 715, 737, 771, 777, 794, 803
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OFFSET

1,2


COMMENTS

Numbers n such that A256271(n) = n.
A necessary condition for n to be in the sequence is that A256271(n)n is even. When A256271(n) is even, A256271(n+1) must be odd; when A256271(n) is odd, A256721(n+1) may be either even or odd, but it appears that it is nearly always even.
The result is that we have long intervals where A256721(n)n is even (e.g. 3369 to 22635), in which members of this sequence are relatively common, and long intervals where A256721(n)n is odd (e.g. 22636 to 67110) which contain no members of this sequence. (End)


LINKS



MAPLE

Res:= 1: count:= 1: v:= 1:
Cands:= [$2..1000]:
for n from 2 do
found:= false;
for j from 1 to nops(Cands) do
if numtheory:issqrfree(v + Cands[j]^2) then
found:= true;
if n = Cands[j] then Res:= Res, n; count:= count+1 fi;
v:= Cands[j]^2;
Cands:= subsop(j=NULL, Cands);
break
fi
od;
if not found then break fi;
od:


PROG

(PARI) print1(1, ", "); v=[1]; n=1; while(#v<10^3, if(issquarefree(n^2+v[#v]^2)&&!vecsearch(vecsort(v), n), if(n==#v, print1(n, ", ")); n=0); n++)


CROSSREFS



KEYWORD



AUTHOR



STATUS

approved



