A129913 a(n) is the number of ways of producing n, with an expression like: +- 1 # 2 # 3 # 4 # 5 # 6 # 7 # 8 # 9, where each # is replaced by any one of +,-,*,/; and the value is computed going left to right.
694, 299, 143, 171, 156, 156, 183, 155, 167, 434, 160, 140, 129, 111, 89, 147, 114, 201, 171, 94, 87, 90, 68, 95, 130, 130, 44, 120, 41, 72, 76, 72, 50, 81, 50, 53, 137, 49, 46, 78, 41, 75, 36, 61, 28, 123, 35, 86, 47, 40, 40, 47, 40, 37, 109, 61, 32, 58, 23, 53
Offset: 0
Examples
Going left-to-right, +1-2/3-4-5*6/7+8*9 = 0; and there are 694 such expressions which yield zero, so a(0)=694.
Links
- Don Reble, Table of n, a(n) for n = 0..1000
- Don Reble, C++ program to compute sequence
Extensions
Corrected and edited by Don Reble, Jun 23 2008