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A293480 Composite numbers k = concat(x,LSD(k)) such that the sum of the aliquot parts of k is equal to the sum of the aliquot parts of x. 0

%I

%S 1711,22991,109999,112639,130733,269119,318293,390319,1138399,1319519,

%T 1841839,2010719,2311919,2581871,6493519,7355839,7533599,8332399

%N Composite numbers k = concat(x,LSD(k)) such that the sum of the aliquot parts of k is equal to the sum of the aliquot parts of x.

%e sum_aliquot_parts(22991) = 361 and sum_aliquot_parts(2299) = 361.

%p with(numtheory): P:=proc(q) local n,p,x; for n from 2 to q do

%p if not isprime(n) then x:=trunc(n/10); if sigma(n)-n=sigma(x)-x then print(n); fi; fi; od; end: P(10^6);

%Y Cf. A010879 (LSD), A001065 (sum of aliquot parts)

%K nonn,base,more

%O 1,1

%A _Paolo P. Lava_, Oct 10 2017

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Last modified June 6 11:14 EDT 2020. Contains 334827 sequences. (Running on oeis4.)