A141545 -id:A141545 - cp's OEIS frontend

84, 140, 224, 308, 364, 476, 532, 644, 812, 868, 1036, 1148, 1204, 1316, 1372, 1484, 1652, 1708, 1876, 1988, 2044, 2212, 2324, 2492, 2716, 2828, 2884, 2996, 3052, 3164, 3556, 3668, 3836, 3892, 4172, 4228, 4396, 4544, 4564, 4676, 4844, 5012, 5068, 5348

Offset: 1

Vassil K. Tintschev (tinchev(AT)sunhe.jinr.ru), Dec 17 2004

If n is of the form p*28, where p is a prime distinct from 2 or 7 then n is in this sequence, note that 28 is a perfect number. The terms in the sequence but not divisible by 28 are 4544, 9272, 14552, 25472, 74992, 495104... - Enrique Pérez Herrero, Apr 15 2012

If p=2^k-57 is prime (cf. A165778), then 2^(k-1)*p is in the sequence: For the first such k=6,7,8,10,16,19,22,28,..., this yields 224, 4544, 25472, 495104, 2145615872, 137424011264, 8795973484544, 36028789368553472, ... - M. F. Hasler, Apr 15 2012

			84 is a term of the sequence because 2*2*3*7 = 84 and 84 - 42 - 28 - 21 - 14 - 12 - 7 - 6 - 4 - 3 - 2 = g(84) = -55.

Enrique Pérez Herrero, Table of n, a(n) for n = 1..3000
F. Firoozbakht and M. F. Hasler, Variations on Euclid's formula for Perfect Numbers, JIS 13 (2010) #10.3.1.

Cf. A005101, A033880.

Cf. A141545, A141546.

[n: n in [1..10^4] |DivisorSigma(1,n) eq 2*n+56]; // Vincenzo Librandi, Jul 30 2015

Select[ Range[5500], DivisorSigma[1, # ] == 2# + 56 &] (* Robert G. Wilson v, Dec 22 2004 *)

cp's OEIS Frontend

A101260 Numbers n whose abundance is 56.

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