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 A254407 #30 Sep 08 2022 08:46:11 %S A254407 0,7,32,86,180,325,532,812,1176,1635,2200,2882,3692,4641,5740,7000, %T A254407 8432,10047,11856,13870,16100,18557,21252,24196,27400,30875,34632, %U A254407 38682,43036,47705,52700,58032,63712,69751,76160,82950,90132,97717,105716,114140,123000 %N A254407 a(n) = n*(n+1)*(11*n +10)/6. %C A254407 Similar sequences of the type m*P(s,m) - Sum_{i=1..m} P(s-1,i), where P(s,m) is the m-th s-gonal number: %C A254407 s=3: A027480(n) = (n+1)*A000217(n+1) - Sum_{i=1..n+1} i; %C A254407 s=4: A162148(n) = (n+1)*A000290(n+1) - Sum_{i=1..n+1} A000217(i); %C A254407 s=5: A245301(n) = (n+1)*A000326(n+1) - Sum_{i=1..n+1} A000290(i); %C A254407 s=6: A085788(n) = (n+1)*A000384(n+1) - Sum_{i=1..n+1} A000326(i); %C A254407 s=7: a(n) = (n+1)*A000566(n+1) - Sum_{i=1..n+1} A000384(i). %H A254407 Vincenzo Librandi, <a href="/A254407/b254407.txt">Table of n, a(n) for n = 0..1000</a> %H A254407 Wikipedia, <a href="http://en.wikipedia.org/wiki/Polygonal_number#Table_of_values">Polygonal numbers: Table of values</a>. %H A254407 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1). %F A254407 G.f.: x*(7 + 4*x)/(1 - x)^4. %F A254407 a(-n) = -A132112(n-1). %F A254407 a(n) = Sum_{k=0..n} A011875(11*k+2). %F A254407 Equivalently, partial sums of A254963. %F A254407 E.g.f.: x*(42 + 54*x + 11*x^2)*exp(x)/6. - _G. C. Greubel_, Mar 31 2021 %e A254407 532 is the 7th term because A000566(7)=112 and Sum_{i=1..7} A000384(i)=252, therefore 7*112-252 = 532. %p A254407 A254407:= n-> n*(n+1)*(11*n+10)/6; seq(A254407(n), n=0..50); # _G. C. Greubel_, Mar 31 2021 %t A254407 Table[n (n + 1) (11 n + 10)/6, {n, 0, 40}] %t A254407 Column[CoefficientList[Series[x (7 + 4 x) / (1 - x)^4, {x, 0, 60}], x]] (* _Vincenzo Librandi_, Jan 31 2015 *) %o A254407 (PARI) vector(40, n, n--; n*(n+1)*(11*n+10)/6) %o A254407 (Sage) [n*(n+1)*(11*n+10)/6 for n in (0..40)] %o A254407 (Magma) [n*(n+1)*(11*n+10)/6: n in [0..40]]; %o A254407 (Maxima) makelist(n*(n+1)*(11*n+10)/6, n, 0, 40); %Y A254407 Cf. A011875, A027480, A057145, A085788, A132112, A162148, A245301, A254963. %K A254407 nonn,easy %O A254407 0,2 %A A254407 _Bruno Berselli_, Jan 30 2015