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Numbers which are the sum of their proper divisors containing the digit 2.
8

%I #10 Mar 09 2024 09:34:35

%S 546,39312,60168,534688,2281353180,272240989636

%N Numbers which are the sum of their proper divisors containing the digit 2.

%C a(7) > 10^12.

%C For each digit d=0..9 there is a corresponding sequence in the OEIS (see Crossrefs), except for d=1, because up to 10^12, only 2654635632 is equal to the sum of its proper divisors which contain the digit 1.

%e The proper divisors of 546 are 1, 2, 3, 6, 7, 13, 14, 21, 26, 39, 42, 78, 91, 182, and 273. Since 2+21+26+42+182+273 = 546, 546 is a term.

%t Select[Range[10^6], # == Plus @@ Select[Most@ Divisors@#, MemberQ[ IntegerDigits@ #, 2] &] &]

%Y Cf. A059461, A059462, A059463, A059464, A059465, A059466, A059467, A059468.

%K nonn,base,less,more

%O 1,1

%A _Giovanni Resta_, May 02 2016