OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
Since 22 = 16+6, because 16 is a square and 6 is a triangular number, 22 is not a term.
23 is a term because there is no representation as S+T or S1+S2 or T1+T2, where S, S1, S2 are squares, and T, T1, T2 are triangular numbers.
MAPLE
N:= 1000: # for terms <= N
S:= [seq(i^2, i=0..floor(sqrt(N)))]: nS:= nops(S):
T:= [seq(i*(i+1)/2, i=0..floor(sqrt(2*N)))]: nT:= nops(T):
sort(convert({$1..N} minus {seq(seq(S[i]+S[j], j=1..i), i=1..nS),
seq(seq(S[i]+T[j], i=1..nS), j=1..nT),
seq(seq(T[i]+T[j], j=1..i), i=1..nT)}, list)); # Robert Israel, May 19 2020
MATHEMATICA
mx = 610; Complement[ Range@ mx, Union@ Flatten@ Table[{i^2 + j^2, i(i + 1)/2 + j^2, i(i + 1)/2 + j(j + 1)/2}, {i, 0, Sqrt[2 mx]}, {j, 0, Sqrt[2 mx]}]] (* Robert G. Wilson v, Nov 29 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Alex Ratushnyak, Nov 03 2015
STATUS
approved