A113286
Numbers k such that S(S(k))=k, with S(n)=sigma(n)/4: 1/4-sociable numbers of order 1 or 2.
Original entry on oeis.org
30240, 32760, 859320, 898560, 2096640, 2178540, 2234232, 23569920, 45532800, 54996480, 61281792, 142990848, 422688000, 436205952, 1379454720
Offset: 1
Cf.
A113546 (1/3-sociable numbers).
Cf.
A355279 (1/4-sociable numbers of order 1 or 3).
A355279
Numbers k such that S(S(S(k))) = k, with S(n) = sigma(n)/4: 1/4-sociable numbers of order 1 or 3.
Original entry on oeis.org
30240, 32760, 2178540, 23569920, 45532800, 46475520, 48933360, 50995620, 60933600, 69995520, 72807696, 142990848
Offset: 1
Cf.
A113286 (1/4 sociable numbers of order <= 2),
A113546 (1/3-sociable numbers).
A356548
Let S(n)=sigma(n)/3. Numbers k such that S^m(k)=k, 1/3-sociable numbers (of any order).
Original entry on oeis.org
120, 672, 7560, 7680, 8064, 8184, 8840, 9600, 10540, 34944, 36576, 38080, 65520, 71680, 75264, 77748, 90272, 472416, 510720, 523776, 605024, 654080, 1100190, 1124352, 14913024, 16149760, 27797760, 33931072, 34012160, 459818240
Offset: 1
120 -> 120 so 120 is a term, a 3-perfect number.
7680 -> 8184 -> 7680, a group of 2 sociable terms.
7560 -> 9600 -> 10540 -> 8064 -> 8840 -> 7560, a group of 5 sociable terms.
34944 -> 38080 -> 36576 -> 34944, a group of 3 sociable terms.
Subsequences:
A005820 (3-perfect),
A113546 (1/3-sociable numbers of order 1 and 2).
Showing 1-3 of 3 results.
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