Split positive integers into extending even groups and sum: 1+2, 3+4+5+6, 7+8+9+10+11+12, 13+14+15+16+17+18+19+20, ...

A061317

Split positive integers into extending even groups and sum: 1+2, 3+4+5+6, 7+8+9+10+11+12, 13+14+15+16+17+18+19+20, ...

Terms

    a(0) =0a(1) =3a(2) =18a(3) =57a(4) =132a(5) =255a(6) =438a(7) =693a(8) =1032a(9) =1467a(10) =2010a(11) =2673a(12) =3468a(13) =4407a(14) =5502a(15) =6765a(16) =8208a(17) =9843a(18) =11682a(19) =13737a(20) =16020a(21) =18543a(22) =21318a(23) =24357a(24) =27672a(25) =31275a(26) =35178a(27) =39393a(28) =43932a(29) =48807

External references