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Numbers k such that k + sigma(k) + sigma(sigma(k)) is a brilliant number (A078972).
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%I #5 Jan 22 2022 19:14:21

%S 2,3,57,63,64,83,85,91,98,133,141,145,149,154,156,187,189,232,247,249,

%T 255,263,279,281,293,310,319,415,419,425,467,512,575,589,593,653,791,

%U 799,813,837,839,970,1019,1103,1113,1145,1247,1259,1427,2183,2223

%N Numbers k such that k + sigma(k) + sigma(sigma(k)) is a brilliant number (A078972).

%e 1103 is in the sequence since 1103 + sigma(1103) + sigma(sigma(1103)) = 71*73 (a brilliant number).

%Y Cf. A078972 (brilliant numbers), A116051.

%K nonn,base

%O 1,1

%A _Giovanni Resta_, Feb 13 2006