A385232 - OEIS

%I #46 Jul 12 2026 03:45:53

%S 17,31,32,57,100,145,177,260,283,320,368,593,945,1124,1649,2169,2530,

%T 3129,3152,3381,4240,5392,7073,8361,16580,18785,20412,23401,32993,

%U 46660,46683,46912,49781,60049,65792,69632,94932,131361,178478,262468,268705,397585,423393,524649,533169,823547,823570

%N Numbers that can be written as s^x + t^y, with 1 < s < t and {s,t} = {x,y}; that is, are of the form s^s + t^t or s^t + t^s.

%H David A. Corneth, <a href="/A385232/b385232.txt">Table of n, a(n) for n = 1..10000</a>

%H Alberto Zanoni, <a href="https://be-numbers.jimdosite.com">BE-numbers</a>

%H A. Zanoni and M. Zanoni, <a href="https://www.anstuocmath.ro/mathematics/anale2026v2/10_ZanoniAlberto_et_all.pdf">Sums of bases-exponents positive integer powers</a>, Analele ştiinţifice ale Universităţii "Ovidius" Constanţa, 34-2 (2026), 197-210.

%e a(1) = 2^3 + 3^2 =  8 +  9 = 17.

%e a(2) = 2^2 + 3^3 =  4 + 27 = 31.

%e a(3) = 2^4 + 4^2 = 16 + 16 = 32.

%e a(4) = 2^5 + 5^2 = 32 + 25 = 57.

%Y Cf. A000312, A001597, A385233 (three addends).

%Y Union of A173054 and A385614.

%K nonn,easy,changed

%O 1,1

%A _Alberto Zanoni_, Jun 28 2025