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A214858
Natural numbers missing from A214857.
2
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
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
Sequence in context: A184915 A108173 A346308 * A186276 A047383 A322534
KEYWORD
nonn,easy
AUTHOR
Philippe Deléham, Mar 09 2013
EXTENSIONS
Extended by T. D. Noe, Mar 11 2013
STATUS
approved