Number of arrays of -2..2 integers x(1..n) with every x(i) in a subsequence of length 1 or 2 with sum zero.
A193642
Number of arrays of -2..2 integers x(1..n) with every x(i) in a subsequence of length 1 or 2 with sum zero.
Terms
- a(0) =1a(1) =5a(2) =13a(3) =37a(4) =105a(5) =297a(6) =841a(7) =2381a(8) =6741a(9) =19085a(10) =54033a(11) =152977a(12) =433105a(13) =1226197a(14) =3471581a(15) =9828661a(16) =27826681a(17) =78782265a(18) =223046553a(19) =631484317a(20) =1787844005a(21) =5061703197a(22) =14330578721a(23) =40572407841a(24) =114867676321a(25) =325210747045
External references
- oeis: A193642