A232501 Numbers k such that distances from k to three nearest squares are three triangular numbers.

1, 10, 15, 19, 26, 197, 253, 325, 631, 1090, 1522, 2395, 3601, 4434, 4625, 6571, 9026, 11026, 11116, 14631, 15454, 19045, 22501, 35722, 38431, 41210, 53036, 61505, 65521, 66239, 69697, 69949, 70291, 85384, 99226, 110890, 152101, 152803, 160021, 168101, 181801, 189631

Offset: 1

Author

Alex Ratushnyak, Feb 23 2014

Keywords

• nonn

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..250

Crossrefs

Cf. A000217, A000290, A234335.

Cf. A232608 (terms that are triangular numbers).

Cf. A000196, A010054, A048760, A048761.

Programs

Haskell

import Data.List (sort)
a232501 n = a232501_list !! (n-1)
a232501_list = filter f [1..] where
   f x = all ((== 1) . a010054) $ init $ sort $
         map (abs . (x -) . (^ 2) . (+ (a000196 x))) [-1..2]
-- Reinhard Zumkeller, Mar 16 2014