Triangular numbers composed of only digits with line segments or both line segments and curves {1, 2, 4, 5, 7}.
A247021
Triangular numbers composed of only digits with line segments or both line segments and curves {1, 2, 4, 5, 7}.
Terms
- a(0) =1a(1) =15a(2) =21a(3) =45a(4) =55a(5) =171a(6) =741a(7) =1225a(8) =1275a(9) =1711a(10) =2145a(11) =2211a(12) =2415a(13) =2775a(14) =5151a(15) =11175a(16) =15225a(17) =21115a(18) =22155a(19) =25425a(20) =44551a(21) =45451a(22) =72771a(23) =77421a(24) =112575a(25) =121771a(26) =124251a(27) =125751a(28) =151525a(29) =211575
External references
- oeis: A247021