A214858 Natural numbers missing from A214857.

5, 8, 12, 15, 19, 22, 26, 29, 32, 36, 39, 43, 46, 49, 53, 56, 60, 63, 67, 70, 73, 77, 80, 84, 87, 90, 94, 97, 101, 104, 108, 111, 114, 118, 121, 125, 128, 131, 135, 138, 142, 145, 149, 152, 155, 159, 162, 166, 169, 172, 176, 179, 183, 186, 189, 193, 196, 200

Offset

1,1

Links

Table of n, a(n) for n=1..58.

Formula

a(n+1) - a(n) = 3 or 4.

Mathematica

tri = Table[n (n + 1)/2, {n, 0, 1000}]; t = Table[Count[tri, _?(# <= n^2 &)], {n, 0, Sqrt[tri[[-1]]]}]; Complement[Range[t[[-1]]], t] (* T. D. Noe, Mar 11 2013 *)

Crossrefs

Cf. A063957, A214857.

Sequence in context: A184915 A108173 A346308 * A186276 A047383 A322534

Adjacent sequences: A214855 A214856 A214857 * A214859 A214860 A214861

Keyword

nonn,easy

Author

Philippe Deléham, Mar 09 2013

Extensions

Extended by T. D. Noe, Mar 11 2013

Status

approved