Alternating sum of 10-gonal (or decagonal) pyramidal numbers.

Terms

a(0) =0a(1) =-1a(2) =10a(3) =-28a(4) =62a(5) =-113a(6) =188a(7) =-288a(8) =420a(9) =-585a(10) =790a(11) =-1036a(12) =1330a(13) =-1673a(14) =2072a(15) =-2528a(16) =3048a(17) =-3633a(18) =4290a(19) =-5020a(20) =5830a(21) =-6721a(22) =7700a(23) =-8768a(24) =9932a(25) =-11193a(26) =12558a(27) =-14028a(28) =15610a(29) =-17305