OFFSET
1,3
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
MAPLE
isA094890 := proc(n)
if isA000217(n) and isA000217(A003132(n)) then
true;
else
false;
end if;
end proc:
for n from 0 to 300 do
T := A000217(n) ;
if isA094890(T) then
printf("%d, ", T) ;
end if;
end do: # R. J. Mathar, Nov 15 2019
MATHEMATICA
tri[n_] := n (n + 1)/2; triQ[n_] := IntegerQ @ Sqrt[8 n + 1]; sumSqDig[n_] := Total @ (IntegerDigits[n]^2); aQ[n_] := triQ @ sumSqDig @ tri[n]; tri /@ Select[Range[0, 578], aQ] (* Amiram Eldar, Dec 23 2019 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Jason Earls, Jun 16 2004
STATUS
approved