A053236 Numbers n such that A053230(n) = 4.

23, 54, 59, 84, 114, 138, 149, 172, 177, 232, 257, 281, 293, 311, 355, 392, 417, 422, 434, 445, 481, 506, 561, 596, 601, 644, 656, 686, 715, 745, 763, 775, 798, 809, 853, 864, 944, 955, 979, 984, 1013, 1018, 1061, 1072, 1140, 1164, 1187, 1192, 1222, 1227

Offset: 1

Author

Asher Auel, Jan 10 2000

Keywords

• nonn

Links

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

Crossrefs

Cf. A000203, A053224, A053230, A053231, A053232, A053233, A053234, A053235, A053237.

Programs

Haskell

import Data.List (elemIndices)
a053236 n = a053236_list !! (n-1)
a053236_list = map (+ 1) $ elemIndices 4 a053230_list
-- Reinhard Zumkeller, May 07 2012

Maple

with(numtheory): f := [seq( `if`((sigma(i+1) > sigma(i)),i,print( )), i=1..8000)];
seq( `if`(f[i+1] - f[i] = 4,i,print( )), i=1..3000);