A331033 a(n) is the least k such that the denominator(sigma(sigma(k))/k) equals n.
1, 30, 3, 32, 5, 864, 7, 128, 9, 10, 11, 96, 13, 3570, 45, 256, 17, 216, 19, 40, 147, 22, 23, 6912, 25, 468, 567, 224, 29, 2520, 31, 416, 33, 374, 35, 147456, 37, 152, 117, 10800, 41, 102816, 43, 88, 135, 46, 47, 768, 49, 21000, 153, 52, 53, 6696, 165, 896, 171, 7424, 59, 36960
Offset: 1
Keywords
Links
- Ray Chandler, Table of n, a(n) for n = 1..10000
Programs
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PARI
a(n) = my(k=n); while (denominator(sigma(sigma(k))/k) != n, k+=n); k;
Comments