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 A348698 Integers m such that sigma(m) + sigma(m+1) + sigma(m+2) - sigma(m+3) <= 0, where sigma is the sum of divisors. 2
 10077, 15117, 20157, 25197, 27717, 37797, 41577, 42837, 45357, 50397, 55437, 65517, 69297, 70557, 75597, 81897, 83157, 85677, 90717, 92397, 98277, 100797, 102957, 105837, 110877, 120117, 120957, 124737, 125997, 128517, 131037, 136077, 138597, 142797, 147417, 147837 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Integers m such that A348688(m) <= 0. At this time, only 2 integers are known with A348688(x)=0: 591357 and 735205677. The least term not == 7 (mod 10) is 3027021. LINKS Michel Marcus, Table of n, a(n) for n = 1..3269 MATHEMATICA s = DivisorSigma[1, Range[1.5*10^5]]; Position[s[[1 ;; -4]] + s[[2 ;; -3]] + s[[3 ;; -2]] - s[[4 ;; -1]], _?(# <= 0 &)] // Flatten (* Amiram Eldar, Oct 30 2021 *) PROG (PARI) isok(m) = sigma(m) + sigma(m+1) + sigma(m+2) - sigma(m+3) <= 0; CROSSREFS Cf. A000203, A348688. Sequence in context: A198484 A252200 A234773 * A203865 A145836 A190293 Adjacent sequences: A348695 A348696 A348697 * A348699 A348700 A348701 KEYWORD nonn AUTHOR Michel Marcus, Oct 30 2021 STATUS approved

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Last modified May 29 00:29 EDT 2024. Contains 372921 sequences. (Running on oeis4.)