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 A374141 #31 Feb 16 2025 08:34:07 %S A374141 7,384,4995,51106,204805,483031,2443431,4674256,10476781,17272531, %T A374141 25600656,60765331,90406956,206602126,332808531,481676406,303826656, %U A374141 435211156,789949306,1406495106,2260173906,2704798281,3220562556,4435869181,5165053156,5309576106,9818788281 %N A374141 a(n) is the smallest number which can be represented as the sum of two distinct nonzero hexagonal numbers in exactly n ways, or -1 if no such number exists. %H A374141 Michael S. Branicky, <a href="/A374141/b374141.txt">Table of n, a(n) for n = 1..39</a> %H A374141 Michael S. Branicky, <a href="/A374141/a374141.txt">Python program for A374141, A374142, and A374143</a> %H A374141 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HexagonalNumber.html">Hexagonal Number</a> %e A374141 a(2) = 384 = 6 + 378 = 153 + 231. %o A374141 (Python) # see linked program %Y A374141 Cf. A000384, A093195, A332989, A342326, A374142, A374143. %K A374141 nonn %O A374141 1,1 %A A374141 _Ilya Gutkovskiy_, Jun 28 2024 %E A374141 a(9)-a(27) from _Michael S. Branicky_, Jun 29 2024