%I #12 Oct 27 2023 22:00:45

%S 5,20,21,29,34,49,50,56,57,65,70,79,80,94,99,108,109,123,132,133,145,

%T 146,154,155,170,171,177,178,198,200,201,227,230,231,239,244,253,254,

%U 259,260,274,277,278,280,289,290,304,307,308,310,327,332,340,341,347

%N n for which values not equal to 2 occur in the expansion of A053238.

%H Reinhard Zumkeller, <a href="/A053240/b053240.txt">Table of n, a(n) for n = 1..10000</a>

%p with(numtheory): f := [seq( `if`((sigma(i) > sigma(i+1)),i,print( )), i=1..5000)];

%p seq( `if`(f[i+1] - f[i] <> 2,i,print( )), i=1..1000);

%o (Haskell)

%o import Data.List (findIndices)

%o a053240 n = a053240_list !! (n-1)

%o a053240_list = map (+ 1) $ findIndices (/= 2) a053238_list

%o -- _Reinhard Zumkeller_, Oct 16 2011

%Y Cf. A000203, A053226, A053238, A053239, A053241 (complement), A053242, A053243, A053244, A053245.

%K nonn

%O 1,1

%A _Asher Auel_, Jan 10 2000