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a(n) = the smallest positive multiple of n such that a(n) is divisible by A001222(a(n)), where A001222(m) is the sum of the exponents in the prime factorization of m.
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%I #8 Oct 04 2015 00:02:03

%S 2,2,3,4,5,6,7,16,18,10,11,12,13,14,30,16,17,18,19,40,42,22,23,24,75,

%T 26,27,56,29,30,31,96,66,34,105,36,37,38,78,40,41,42,43,88,45,46,47,

%U 96,147,100,102,104,53,216,165,56,114,58,59,60,61,62,63,256,195,66,67,136,138

%N a(n) = the smallest positive multiple of n such that a(n) is divisible by A001222(a(n)), where A001222(m) is the sum of the exponents in the prime factorization of m.

%e For n = 25, checking: 1*25 = 25 = 5^2. The sum of the exponents in the prime-factorization of 5^2 is 2. 2 does not divide 25. 2*25 = 50 = 2^1 *5^2. The sum of the exponents is 1+2=3. 3 does not divide 50. 3*25 = 75 = 3^1 *5^2. The sum of the exponents is 3. Now, 3 does divide 75. So a(25) = 75.

%p A001222 := proc(n) numtheory[bigomega](n) ; end: A141286 := proc(n) local k ; for k from 1 do if k*n > 1 then if (k*n) mod A001222(k*n) = 0 then RETURN( k*n ) ; fi; fi; od: end: seq(A141286(n),n=1..80) ; # _R. J. Mathar_, Feb 19 2009

%Y Cf. A001222.

%K nonn

%O 1,1

%A _Leroy Quet_, Aug 01 2008

%E More terms from _R. J. Mathar_, Feb 19 2009