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A129317 The second of the pair of consecutive integers n and n+1 such that sopfr(n) divides sopfr(n+1), where sopfr(n) is the sum of the prime factors of n, counting multiplicity. A129316 is the first element n of the pair. A generalization of Ruth-Aaron pairs (A006145). 4

%I

%S 6,9,16,78,126,161,253,497,715,949,981,1046,1054,1261,1331,1379,1405,

%T 1431,1509,1521,1611,1751,1863,1891,2171,2492,2681,2822,3095,3101,

%U 3249,3401,3592,3611,3653,3809,4186,4192,4385,4453,4501,4599,4907,5121,5146

%N The second of the pair of consecutive integers n and n+1 such that sopfr(n) divides sopfr(n+1), where sopfr(n) is the sum of the prime factors of n, counting multiplicity. A129316 is the first element n of the pair. A generalization of Ruth-Aaron pairs (A006145).

%F sopfr(n+1) mod sopfr(n) = 0.

%e a(6)=161 since sopfr(160)=sopfr(2^5*5)=10+5=15 and sopfr(161)=sopfr(7*23)=30.

%Y Cf. A001414, A006145, A039752, A129316, A129318, A129319.

%K easy,nonn

%O 1,1

%A _Walter Kehowski_, Apr 09 2007

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Last modified January 17 15:16 EST 2019. Contains 319225 sequences. (Running on oeis4.)