Write 1, 2, 3, 4, ... counterclockwise in a hexagonal spiral around 0 starting left down, then a(n) is the sequence found by reading from 0 in the vertical upward direction.

A063436

Write 1, 2, 3, 4, ... counterclockwise in a hexagonal spiral around 0 starting left down, then a(n) is the sequence found by reading from 0 in the vertical upward direction.

Terms

    a(0) =0a(1) =15a(2) =54a(3) =117a(4) =204a(5) =315a(6) =450a(7) =609a(8) =792a(9) =999a(10) =1230a(11) =1485a(12) =1764a(13) =2067a(14) =2394a(15) =2745a(16) =3120a(17) =3519a(18) =3942a(19) =4389a(20) =4860a(21) =5355a(22) =5874a(23) =6417a(24) =6984a(25) =7575a(26) =8190a(27) =8829a(28) =9492a(29) =10179

External references