cp's OEIS Frontend

A353386 Sums of two squares obtained by expanding a k X k matrix to (k+1) X (k+1) and taking the not yet seen squared distances of all positions in the matrix.

%I A353386 #9 Apr 16 2022 09:40:10
%S A353386 1,2,4,5,8,9,10,13,18,16,17,20,25,32,26,29,34,41,50,36,37,40,45,52,61,
%T A353386 72,49,53,58,65,74,85,98,64,68,73,80,89,100,113,128,81,82,90,97,106,
%U A353386 117,130,145,162,101,104,109,116,125,136,149,164,181,200,121,122,137,146,157,170,185,202,221,242
%N A353386 Sums of two squares obtained by expanding a k X k matrix to (k+1) X (k+1) and taking the not yet seen squared distances of all positions in the matrix.
%C A353386 The terms are a permutation of the positive terms of A001481.
%e A353386 The sequence can be viewed as a table with line lengths A047800(k+1) - A047800(k), in which the not yet seen sums of squares form a table line. The table starts:
%e A353386    1,  2,
%e A353386    4,  5,  8,
%e A353386    9, 10, 13, 18,
%e A353386   16, 17, 20, 25, 32,
%e A353386   26, 29, 34, 41, 50,
%e A353386   36, 37, 40, 45, 52, 61, 72,
%e A353386   49, 53, 58, 65, 74, 85, 98
%o A353386 (PARI) a353386(nmax)={my(v=vectorsmall(2*nmax^2)); for(n=1,nmax,
%o A353386 for(k=0,n,my(s=n^2+k^2); if(!v[s],print1(s,", ");v[s]++));print())};
%o A353386 a353386(11)
%Y A353386 Cf. A001481, A047800.
%Y A353386 Cf. A353387 (first term in lines), A001105 (last term in lines).
%K A353386 nonn,tabf
%O A353386 1,2
%A A353386 _Hugo Pfoertner_, Apr 15 2022