The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A076462 Sum of squares of numbers that can be written as t*n + u*(n+1) for nonnegative integers t,u in exactly three ways. 1
 41, 1471, 12938, 62870, 218555, 611821, 1471316, 3161388, 6227565, 11448635, 19895326, 32995586, 52606463, 81092585, 121411240, 177204056, 252895281, 353796663, 486218930, 657589870, 876579011, 1153228901, 1499092988, 1927380100, 2453105525, 3093248691 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 REFERENCES Fred. Schuh, Vragen betreffende een onbepaalde vergelijking, Nieuw Tijdschrift voor Wiskunde, 52 (1964-1965) 193-198. LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 FORMULA a(n) = n*(n+1)*(55*n^4+74*n^3+6*n^2-13*n+1)/6. G.f.: x*(41+1184*x+3502*x^2+1760*x^3+113*x^4)/(1-x)^7. MAPLE seq(1/6*n*(n+1)*(55*n^4+74*n^3+6*n^2-13*n+1), n=1..30); MATHEMATICA CoefficientList[Series[(41 + 1184 x + 3502 x^2 + 1760 x^3 + 113 x^4)/(1 - x)^7, {x, 0, 50}], x] (* Vincenzo Librandi, Dec 30 2013 *) PROG (Magma) [n*(n+1)*(55*n^4+74*n^3+6*n^2-13*n+1)/6: n in [1..50]]; // Vincenzo Librandi, Dec 30 2013 CROSSREFS Cf. A076389, A076460-A076465. Sequence in context: A094455 A239251 A197527 * A163050 A305863 A180667 Adjacent sequences: A076459 A076460 A076461 * A076463 A076464 A076465 KEYWORD nonn,easy AUTHOR Floor van Lamoen, Oct 13 2002 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified February 25 00:32 EST 2024. Contains 370308 sequences. (Running on oeis4.)