This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A387292 #26 Sep 04 2025 10:53:10 %S A387292 3,4,6,8,9,10,12,27,30,32,44,45,51,52,68,75,81,96,99,100,105,112,114, %T A387292 152,164,171,186,188,190,192,204,225,230,238,243,246,255,260,272,284, %U A387292 304,308,316,322,340,342,348,352,354,357,360,370,375,380,385,396,400,406,426,430,435,441,448,456,460,464,474,476 %N A387292 Integers x such that there exist three numbers y,z,and t with x<=y<=z<=t such that psi(x) = psi(y) = psi(z) = psi(t) = (x + y + z + t)/3. %C A387292 The numbers x, y, z and t form a psi-amicable quadruple according to Dimitrov's definition. %H A387292 S. I. Dimitrov, <a href="https://arxiv.org/abs/2508.02318">On psi-amicable numbers and their generalizations</a>, arXiv:2508.02318 [math.NT], 2025. %e A387292 44 is in the sequence since psi(44) = psi(46) = psi(55) = psi(71) = 72 = (44 + 46 + 55 + 71)/3. %e A387292 45 is in the sequence since psi(45) = psi(45) = psi(55) = psi(71) = 72 = (45 + 45 + 55 + 71)/3. %Y A387292 Cf. A001615, A385852, A386727, A386901, A386933, A387291, A387486. %K A387292 nonn,easy,new %O A387292 1,1 %A A387292 _S. I. Dimitrov_, Aug 25 2025