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A255968 Numbers n such that antisigma(n) contains n as a substring. 1

%I

%S 24,57,204,411,559,2004,2440,3935,6616,8640,20004,34939,55827,61009,

%T 64599,79747,87113,87269,96513,481557,621265,647532,702893,704682,

%U 797465,2000004,2385120

%N Numbers n such that antisigma(n) contains n as a substring.

%C Any number of the form 20...04, with a number of consecutive zeros not equal to 6*k+4 (with k = 0, 1, 2, 3,...), appears to belong to the sequence.

%e antisigma(24) = (24*25) / 2 - sigma(24) = 300 - 60 = 240 and 24 is a substring;

%e antisigma(57) = (57*58) / 2 - sigma(57) = 1653 - 80 = 1573 and 57 is a substring.

%p with(numtheory): P:=proc(q) local a,b,c,d,j,n;

%p for n from 1 to q do a:=n; b:=n*(n+1)/2-sigma(n); c:=ilog10(n)+1; d:=ilog10(b)+1;

%p for j from 1 to d-c+1 do if n=(b mod 10^c) then print(n); break; else b:=trunc(b/10);

%p fi; od; od; print(); end: P(10^9);

%Y Cf. A024816.

%K nonn,base

%O 1,1

%A _Paolo P. Lava_, Mar 12 2015

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Last modified October 16 11:59 EDT 2019. Contains 328056 sequences. (Running on oeis4.)