A026469 a(1) = 1; for n > 1, a(n) = least positive integer > a(n-1) and not equal to a(i)^2 + a(j)^2 for 1<=i<=j<=n-1.
1, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 19, 20, 21, 22, 23, 24, 27, 28, 29, 30, 31, 33, 35, 36, 38, 39, 40, 42, 43, 44, 46, 47, 48, 49, 51, 53, 54, 55, 56, 57, 59, 60, 62, 63, 64, 66, 67, 68, 69, 70, 71, 75, 76, 77, 78, 79
Offset: 1
Keywords
Programs
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Maple
# return true if 'candid' is allowed (not a sum of squares) A026469aux := proc(a,candid) local i,j ; for j from 1 to nops(a) do for i from 1 to j do if (op(i,a))^2+(op(j,a))^2 = candid then RETURN(false) ; fi ; od ; od ; RETURN(true) ; end: A026469 := proc(nmax) local a,candidat ; a := [1] ; while nops(a) < nmax do candidat := op(nops(a),a)+1 ; while A026469aux(a,candidat) = false do candidat := candidat+1 ; od ; a := [op(a),candidat] ; od: RETURN(a) ; end: A026469(60) ; # R. J. Mathar, Nov 01 2006
Extensions
Corrected by Franklin T. Adams-Watters, Oct 25 2006
Definition corrected by N. J. A. Sloane, Nov 01 2006