A253169 Smallest m such that A256188(m) = n.

1, 2, 9, 5, 6, 36, 10, 11, 12, 100, 17, 18, 19, 20, 225, 26, 27, 28, 29, 30, 441, 37, 38, 39, 40, 41, 42, 784, 50, 51, 52, 53, 54, 55, 56, 1296, 65, 66, 67, 68, 69, 70, 71, 72, 2025, 82, 83, 84, 85, 86, 87, 88, 89, 90, 3025, 101, 102, 103, 104, 105, 106, 107

Offset: 1

Author

Reinhard Zumkeller, Mar 26 2015

Keywords

• nonn

Comments

A256188(a(n)) = n and A256188(m) != n for m < a(n).

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A256188, A000537, A010054, A000290.

Programs

Haskell

import Data.List (elemIndex); import Data.Maybe (fromJust)
a253169 = (+ 1) . fromJust . (`elemIndex` a256188_list)

Formula

a(n) = if n triangular then n^2 else A004202(n + 1 - A002024(n)).