add test

tests/formula/program-formula.txt

@@ -39,6 +39,7 @@ A001478: a(n) = -n-1
 A001489: a(n) = -n
 A001542: a(n) = 3*a(n-1)+2*b(n-1), a(1) = 2, a(0) = 0, b(n) = 4*a(n-1)+3*b(n-1), b(1) = 3, b(0) = 1
 A001611: a(n) = A000045(n)+1, A000045(n) = A000045(n-1)+A000045(n-2), A000045(1) = 1, A000045(0) = 0
+A001687: a(n) = a(n-2)+a(n-5), a(4) = 0, a(3) = 1, a(2) = 0, a(1) = 1, a(0) = 0
 A001715: a(n) = b(n+3)/6, b(n) = n*b(n-1), b(0) = 1
 A001911: a(n) = b(n)-2, b(n) = b(n-1)+b(n-2), b(1) = 3, b(0) = 2
 A001923: a(n) = n^n+a(n-1), a(0) = 0

tests/programs/oeis/001/A001687.asm

@@ -0,0 +1,15 @@
+; A001687: a(n) = a(n-2) + a(n-5).
+; 0,1,0,1,0,1,1,1,2,1,3,2,4,4,5,7,7,11,11,16,18,23,29,34,45,52,68,81,102,126,154,194,235,296,361,450,555,685,851,1046,1301,1601,1986,2452,3032,3753,4633,5739,7085,8771,10838,13404,16577,20489,25348,31327,38752,47904,59241,73252,90568,112004,138472,171245,211724,261813,323728,400285,494973,612009,756786,935737,1157071,1430710,1769080,2187496,2704817,3344567,4135527,5113647
+
+mov $2,1
+lpb $0
+  sub $0,1
+  mov $5,$4
+  mov $4,$2
+  add $4,$6
+  mov $2,$1
+  mov $1,$3
+  mov $3,$6
+  mov $6,$5
+lpe
+mov $0,$4