implement A000245

src/oeis/A000108.ts

@@ -4,6 +4,5 @@ import { factorial } from '../utils'
 export default function* A000108(): Generator<bigint> {
   for (let n = 0n; /*∞*/; n++) {
     yield factorial(2n * n) / factorial(n + 1n) / factorial(n)
-
   }
 }

src/oeis/A000245.ts

@@ -1,35 +1,10 @@
+import { factorial } from '../utils'
+
 // a(n) = 3*(2*n)!/((n+2)!*(n-1)!).
 export default function* A000245(): Generator<bigint> {
-  for (const n of [
-    0n,
-    1n,
-    3n,
-    9n,
-    28n,
-    90n,
-    297n,
-    1001n,
-    3432n,
-    11934n,
-    41990n,
-    149226n,
-    534888n,
-    1931540n,
-    7020405n,
-    25662825n,
-    94287120n,
-    347993910n,
-    1289624490n,
-    4796857230n,
-    17902146600n,
-    67016296620n,
-    251577050010n,
-    946844533674n,
-    3572042254128n,
-    13505406670700n,
-    51166197843852n,
-    194214400834356n,
-  ]) {
-    yield n
+  yield 0n
+  for (let n = 1n; /*∞*/; n++) {
+    // 3*(2*n)!/((n+2)!*(n-1)!)
+    yield 3n * factorial(2n * n) / ( factorial(n + 2n) * factorial(n - 1n) )
   }
 }