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 A225256 #11 Sep 07 2023 07:15:45 %S A225256 3,7,14,23,38,47,68,87,115,147,183,203,245,291,341,395,453,503,568, %T A225256 619,691,767,827,887,973,1063,1157,1255,1357,1463,1573,1631,1747,1867, %U A225256 1991,2119,2251,2317,2455,2597,2743,2893,3047,3205,3367,3533,3703,3791,3967 %N A225256 Minimum value unattainable as the sum of 2 attained values of a*b with a,b 0..n integers. %C A225256 Related to A225252. %H A225256 R. H. Hardin, <a href="/A225256/b225256.txt">Table of n, a(n) for n = 1..1000</a> %o A225256 (PARI) a(n) = my(v=setbinop((x,y)->x+y, setbinop((x,y)->x*y, [0..n]))); for(k=0, vecmax(v)+1, if (!vecsearch(v, k), return(k))); \\ _Michel Marcus_, Sep 07 2023 %Y A225256 Cf. A225252, A225253. %K A225256 nonn %O A225256 1,1 %A A225256 _R. H. Hardin_, May 04 2013