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

1,2

Links

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

Prog

(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

Crossrefs

Cf. A000217, A000290, A234335.

Cf. A232608 (terms that are triangular numbers).

Cf. A000196, A010054, A048760, A048761.

Sequence in context: A135363 A118717 A181529 * A138593 A362010 A004259

Adjacent sequences: A232498 A232499 A232500 * A232502 A232503 A232504

Keyword

nonn

Author

Alex Ratushnyak, Feb 23 2014

Status

approved