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 A051650 #42 Jul 02 2025 16:01:58 %S A051650 0,23,53,120,211,1340,1341,1342,1343,1344,2179,3967,15704,15705,16033, %T A051650 19634,19635,24281,31428,31429,31430,31431,31432,31433,38501,58831, %U A051650 155964,203713,206699,370310,370311,370312,370313,370314,370315,370316 %N A051650 Lonely numbers: distance to closest prime sets a new record. %H A051650 Charles R Greathouse IV and Giovanni Resta, <a href="/A051650/b051650.txt">Table of n, a(n) for n = 0..211</a> (terms < 10^14, first 156 terms from Charles R Greathouse IV) %e A051650 23 is 4 units away from the closest prime (not including itself), so 23 is in the sequence. %t A051650 d[0] = 2; d[k_] := Min[k - NextPrime[k, -1], NextPrime[k] - k]; a[0] = 0; a[n_] := a[n] = (k = a[n-1] + 1; record = d[a[n-1]]; While[d[k] <= record, k++]; k); Table[a[n], {n, 0, 35}] (* _Jean-François Alcover_, Jan 16 2012 *) %t A051650 dcp[n_]:=Min[n-NextPrime[n,-1],NextPrime[n]-n]; DeleteDuplicates[Table[{n,dcp[n]},{n,0,375000}],GreaterEqual[#1[[2]],#2[[2]]]&][[;;,1]] (* _Harvey P. Dale_, Feb 23 2023 *) %o A051650 (PARI) print1(0);w=2;p=2;q=3;forprime(r=5,1e9,if(p+w+w<q,for(t=p+w+1,(q+p)\2,print1(", "t));w=(q-p)\2);t=min(q-p,r-q);if(t>w,w=t;print1(", "q));p=q;q=r) \\ _Charles R Greathouse IV_, Jan 16 2012 %Y A051650 Related sequences: A023186-A023188, A046929-A046931, A051650, A051652, A051697-A051702, A051728-A051730. %Y A051650 Distances are in A051730. %K A051650 nonn,nice %O A051650 0,2 %A A051650 _N. J. A. Sloane_ %E A051650 More terms from _James Sellers_, Dec 23 1999 and from _Jud McCranie_, Jun 16 2000