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First differences between n for which sigma(n) > sigma(n+1), which are not 2.
7

%I #6 Oct 27 2023 22:00:45

%S 4,1,1,4,4,1,1,1,1,4,4,1,1,4,4,1,1,4,1,1,1,1,3,1,1,1,1,1,4,3,1,4,1,1,

%T 4,4,1,1,3,1,4,1,1,4,1,1,4,1,1,4,4,4,3,1,1,1,4,4,3,1,1,1,4,4,1,1,1,1,

%U 4,1,1,1,1,4,3,1,4,4,1,1,4,4,1,1,3,1,3,1,1,1,1,1,4,4,1,1,4,1,1,4,4,3,1,3,1

%N First differences between n for which sigma(n) > sigma(n+1), which are not 2.

%F The expansion of A053238 excluding 2's. a(n) = A053238(A053240(n)).

%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,f[i+1] - f[i],print( )), i=1..2000);

%Y Cf. A000203, A053226, A053238, A053240, A053241, A053242, A053243, A053244, A053245.

%K nonn

%O 1,1

%A _Asher Auel_, Jan 10 2000

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Last modified September 23 18:03 EDT 2024. Contains 376178 sequences. (Running on oeis4.)