A348698 Integers m such that sigma(m) + sigma(m+1) + sigma(m+2) - sigma(m+3) <= 0, where sigma is the sum of divisors.

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

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