23353

Appears in sequences

• [ n(n-1)(n-2)(n-3)/13 ].at n=25A011923
• a(n) = s(1)*t(n) + s(2)*t(n-1) + ... + s(k)*t(n+1-k), where k = floor((n+1)/2), s = (natural numbers >= 2), t = (Fibonacci numbers).at n=17A024309
• a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers >= 2), t = (Fibonacci numbers).at n=16A024872
• Number of domino tilings of a 7-pillow of order n.at n=8A112839
• a(n) = least k such that the remainder when 17^k is divided by k is n.at n=39A128157
• Denominators of an Egyptian fraction for 1/Sqrt[22] = 0.21320071635561...at n=2A144997
• a(n) is the smallest number in Spanish with n consonants.at n=23A157903
• Triangle of coefficients of polynomials u(n,x) jointly generated with A210861; see the Formula section of A210861.at n=40A210860
• Smallest k > 0 such that (5^n+k)*5^n-1 and (5^n+k)*5^n+1 are a twin prime pair.at n=42A212487
• Number of n X 2 binary arrays whose sum with another n X 2 binary array containing no more than a single 1 has rows and columns in lexicographically nondecreasing order.at n=18A225894
• Volume of torus (rounded down) with major radius = n and minor radius = n/3.at n=21A228641
• Least k such that at least half of the last n digits of 2^k are 9.at n=14A280660
• Positive integers that have exactly ten representations of the form 1 + p1 * (1 + p2* ... * (1 + p_j)...), where [p1, ..., p_j] is a (possibly empty) list of distinct primes.at n=28A317400
• a(n) = Sum_{k=1..n} k^2 * floor(n/k)^3.at n=19A350124