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 A132156 #9 Nov 30 2019 09:12:27 %S A132156 13,148,1003,16141,117547,917053,15502289,114274754,909482399, %T A132156 15471962269,115061008452,917885746619,15675637954053,116877859994048, %U A132156 933643385166035,15975162211603393,119196492782053456,952870691477908028,16319572144410372393,121792577413939691253 %N A132156 Sum of all n-digit Stern numbers. %e A132156 Sum of all 1-digit Stern numbers is 1 + 1 + 2 + 3 + 6 = 13. %e A132156 Sum of all 2-digit Stern numbers is 11 + 20 + 40 + 77 = 148. %e A132156 Sum of all 3-digit Stern numbers is 148 + 285 + 570 = 1003. %t A132156 stern[1] = 1; stern[n_] := stern[n] = Sum[stern[k], {k, n - Ceiling[(Sqrt[8*n -7]-1)/2], n-1}]; digNum[n_] := Length @ IntegerDigits[n]; digCount = 0; sum = 0; cumsum = {}; Do[s = stern[n]; If[digNum[s] > digCount, digCount++; AppendTo[cumsum, sum]]; sum += s, {n, 1, 25}]; Differences[cumsum] (* _Amiram Eldar_, Nov 30 2019 *) %Y A132156 Cf. A005230. %K A132156 nonn,base,less %O A132156 1,1 %A A132156 _Parthasarathy Nambi_, Nov 01 2007 %E A132156 More terms from _Amiram Eldar_, Nov 30 2019