20339

Appears in sequences

• Number of partitions of n into parts not of the form 23k, 23k+10 or 23k-10. Also number of partitions with at most 9 parts of size 1 and differences between parts at distance 10 are greater than 1.at n=37A035998
• Numerator of 1 + 1/2 + 2/3 + 3/4 + ... + (n-1)/n.at n=10A061483
• Main diagonal of number square A081206.at n=12A081207
• (k^2)-th k-smooth number for k = prime(n).at n=19A133581
• T(n,k) = 4*A046802(n,k) - 3*A007318(n,k), triangle read by rows (0 <= k <= n).at n=31A168289
• T(n,k) = 4*A046802(n,k) - 3*A007318(n,k), triangle read by rows (0 <= k <= n).at n=32A168289
• Composite numbers and 1 which yield a prime whenever a 3 is inserted anywhere in them (including at the beginning or end).at n=23A216166
• a(0) = 0. a(n) is the number of distinct sums formed by [a(0), ... a(n-1)] + [a(0), ... a(n-1)] + ... + [a(0), ... a(n-1)], where [a(0), ... a(n-1)] is repeated n times.at n=10A247210
• Number of length n 1..(2+2) arrays with no leading or trailing partial sum equal to a prime and no consecutive values equal.at n=28A254212
• The sum of the numbers on straight lines of incrementing length n when drawn over numbers of the square spiral, where each line contains numbers which sum to the minimum possible value, and each number on the spiral can only be in one line. If two or more lines exist with the same sum the one containing the smallest number is chosen.at n=29A340974
• Sociable totient numbers of order 3: numbers k such that s(s(s(k))) = k, but s(k) != k, where s(k) = A092693(k) is the sum of iterated phi function.at n=0A343243
• Numbers p^2*q, p > q odd primes such that q divides p+1.at n=15A350245
• Numbers k such that sigma(k) = psi(k) + 2 * tau(k).at n=32A387962