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 A225881 Numbers that can be expressed as the product of largest triangular proper divisor and the sum of triangular proper divisors. 3

%I

%S 285,5016,24021,142350,145665,154602,204450,318912,474192,843402,

%T 1196690,1283664,1670250,2739021,3412950,4255776,5052135,6054880,

%U 6272140,6433440,6493728,6650712,6728190,7156044,7323030,7797750,9379350,10108840,10188864

%N Numbers that can be expressed as the product of largest triangular proper divisor and the sum of triangular proper divisors.

%H Donovan Johnson, <a href="/A225881/b225881.txt">Table of n, a(n) for n = 1..300</a>

%e 5016 = 66*(66+6+3+1).

%o (PARI)

%o msumprop(n)={k=1;i=1;s=0;d=1;while(k<=n\2,if(n/k==n\k,d=k;s+=d);i+=1;k+=i);s*=d;return(s)}

%o {for (n=2,10^7,if(n==msumprop(n),print(n)))}

%Y Cf. A225880, A225882.

%K nonn

%O 1,1

%A _Antonio RoldÃ¡n_, May 19 2013

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Last modified October 18 00:21 EDT 2019. Contains 328135 sequences. (Running on oeis4.)