Irregular triangle read by rows: row 0 is {2}; if row n is {r_1, ..., r_k} then row n+1 is {r_k 1's, r_{k-1} 2's, r_{k-2} 3's, etc.}.
A012257
Irregular triangle read by rows: row 0 is {2}; if row n is {r_1, ..., r_k} then row n+1 is {r_k 1's, r_{k-1} 2's, r_{k-2} 3's, etc.}.
Terms
- a(0) =2a(1) =1a(2) =1a(3) =1a(4) =2a(5) =1a(6) =1a(7) =2a(8) =1a(9) =1a(10) =2a(11) =3a(12) =1a(13) =1a(14) =1a(15) =2a(16) =2a(17) =3a(18) =4a(19) =1a(20) =1a(21) =1a(22) =1a(23) =2a(24) =2a(25) =2a(26) =3a(27) =3a(28) =4a(29) =4
External references
- oeis: A012257