Triangular numbers such that both the number formed by the first floor((k+1)/2) digits and the remaining part (if any) are triangular numbers, where k is the number of digits.
A068821
Triangular numbers such that both the number formed by the first floor((k+1)/2) digits and the remaining part (if any) are triangular numbers, where k is the number of digits.
Terms
- a(0) =1a(1) =3a(2) =6a(3) =10a(4) =36a(5) =66a(6) =136a(7) =300a(8) =378a(9) =666a(10) =2145a(11) =3655a(12) =10153a(13) =21528a(14) =66066a(15) =78210a(16) =91378a(17) =190036a(18) =210276a(19) =378015a(20) =406351a(21) =630003a(22) =666435a(23) =741153a(24) =946000a(25) =990528a(26) =1537381a(27) =1710325a(28) =3788128a(29) =4652775
External references
- oeis: A068821