176890

Appears in sequences

• a(n) = C(3+n, n) + C(4+n, n) + C(5+n, n) + C(6+n, n).at n=18A062966
• Number of n X n binary arrays symmetric about main diagonal with all ones connected only in two by two blocks.at n=10A145860
• Number of n X n binary arrays symmetric about the diagonal and under 90-degree rotation with all ones connected only in two by two blocks.at n=22A145862
• Integers n such that the century defined by the interval [100n+1, 100n+100] (i.e., the (n+1)-st century) contains exactly two Ormiston prime pairs and no other primes.at n=4A162894