A333503 - OEIS

%I #11 Apr 08 2020 16:32:52

%S 630,630,630,630,630,630,630,420,210,450,180,210,420,180,450,210,330,

%T 90,420,210,420,210,630,630,630,630,420,210,630,630,630,210,420,630,

%U 630,630,630,630,630,90,330,210,630,630,630,210,330,90,630,210,420,630,630

%N Differences between consecutive odd abundant numbers.

%C a(n) = A005231(n+1) - A005231(n).

%C Since 945+1890*k is odd and abundant for all k, 1890 is the maximal term that occurs. The first time it occurs is for a(274)=1890, and the involved odd abundant numbers are 135135 and 137025.

%C Clearly 2 is the minimal term that can occur. For an example, see comment to A294025.

%H Jeppe Stig Nielsen, <a href="/A333503/b333503.txt">Table of n, a(n) for n = 1..1000</a>

%t Differences@ Select[Range[947, 3*10^4 + 1, 2], DivisorSigma[1, #] > 2 # &] (* _Michael De Vlieger_, Mar 25 2020 *)

%o (PARI) my(oldn=945); forstep(n=947, 5*10^4, 2, if(sigma(n)>2*n, print1(n-oldn, ", "); oldn=n))

%Y Cf. A005231, A294025.

%K nonn

%O 1,1

%A _Jeppe Stig Nielsen_, Mar 24 2020