A334688 Numbers missing from Pascal's spiral A334742.

9, 11, 13, 15, 16, 18, 19, 21, 22, 24, 25, 26, 28, 29, 30, 31, 33, 34, 35, 36, 38, 39, 40, 41, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 54, 56, 57, 58, 59, 60, 61, 63, 64, 65, 66, 67, 68, 70, 71, 72, 73, 74, 75, 76, 78, 79, 80

Offset: 1

Author

N. J. A. Sloane, May 10 2020

Keywords

• nonn

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A334742.

Programs

Maple

V:= Array(-10..10,-10..10): t:=1:
i:= 1: j:= 0: V[0,0]:= 1: R:= NULL:
do
  u:= V[i-1,j]+V[i+1,j]+V[i,j-1]+V[i,j+1];
  V[i,j]:= u;
  R:= R, $(t+1)..(u-1);
  t:= u;
  if u > 100 then break fi;
  if  j > -i and j < i then j:= j+1
  elif i > -j and i <= j then i:= i-1
  elif i < j and j <= -i then j:= j-1
  else i:= i+1
  fi;
od:
R; # Robert Israel, May 15 2020