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 A226805 #12 Nov 19 2013 14:18:00 %S A226805 1,7,70,877,13316,237799,4885980,113566121,2946476764,84417530491, %T A226805 2647176188372,90183424037293,3316840864313484,130985236211745959, %U A226805 5528094465439087876,248308899812296990033,11827417687501017074876,595470029978391175571923 %N A226805 P_n(n+1) where P_n(x) is the polynomial of degree n-1 which satisfies P_n(i) = i^i for i = 1,...,n. %H A226805 Alois P. Heinz, <a href="/A226805/b226805.txt">Table of n, a(n) for n = 1..100</a> %e A226805 P_3(x) = 18 - 27*x + 10*x^2; a(3) = P_3(3+1) = 70. %t A226805 P[n_][x_] = Sum[a[i]*x^i, {i, 0, n - 1}];ecu[n_] := Table[P[n][i] == i^i, {i, 1, n}];PP[n_][x_] := P[n][x] /. Solve[ecu[n]][[1]];Table[PP[i][i + 1], {i, 1, 22}] %t A226805 a[n_] := InterpolatingPolynomial[Table[{i, i^i}, {i, n}], n+1]; Array[a, 20] (* _Giovanni Resta_, Jun 18 2013 *) %o A226805 (PARI) a(n)=subst(polinterpolate(vector(n,i,i^i)),'x,n+1) \\ _Charles R Greathouse IV_, Nov 19 2013 %Y A226805 Cf. A140119, A140118, A126130, A000312. %K A226805 nonn %O A226805 1,2 %A A226805 _José María Grau Ribas_, Jun 18 2013