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

1,2

Links

Table of n, a(n) for n=1..60.

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

Crossrefs

A022544 is a subsequence.

Cf. A026468.

Sequence in context: A026466 A304806 A304810 * A258187 A039237 A039181

Adjacent sequences: A026466 A026467 A026468 * A026470 A026471 A026472

Keyword

nonn

Author

Clark Kimberling

Extensions

Corrected by Franklin T. Adams-Watters, Oct 25 2006

Definition corrected by N. J. A. Sloane, Nov 01 2006

Status

approved