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%I #17 Jan 04 2020 09:51:35
%S 2,3,7,75,86,91,1863,2763,3595,5451,6031,7734,8023,9631,35403,41391,
%T 53431,63847,64294,148391,205556,237992,374715,381440,404775,442755,
%U 510283,546422,917035,1149111,1291895,1563158,2197526,2610182,2693035,2730524,2804331,3020715,3547982,4365950
%N Integers m such that A064992(m) = A064992(m+1).
%H Amiram Eldar, <a href="/A065002/b065002.txt">Table of n, a(n) for n = 1..138</a> (terms below 10^10)
%t usigma[1] = 1; usigma[n_] := Times @@ (1 + Power @@@ FactorInteger[n]); seq = {}; u1 = usigma[1]; u2 = usigma[2]; Do[u3 = usigma[n]; If[u3 == 2*u2 - u1, AppendTo[seq, n - 2]]; u1 = u2; u2 = u3, {n, 3, 10^4}]; seq (* _Amiram Eldar_, Jan 04 2020 *)
%o (PARI) usigma(n) = sumdiv(n, d, if(gcd(d, n/d)==1, d));
%o lista(nn) = {u = vector(nn, n, usigma(n)); v = vector(#u-1, n, u[n+1] - u[n]); w = vector(#v-1, n, v[n+1] - v[n]); x = select(y->y==0, w, 1);} \\ _Michel Marcus_, Aug 12 2018
%Y Cf. A064992.
%K nonn
%O 1,1
%A _Jason Earls_, Nov 01 2001
%E More terms from _Michel Marcus_, Aug 12 2018
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