26867

Appears in sequences

• Odd composites (including 1 in the count) where the number 3 mod 4 equals the number 1 mod 4.at n=4A093181
• Pentagonal numbers (A000326) whose digit reversal is a semiprime (A001358).at n=40A115709
• Smallest number m such that prime(n) is a factor of both m and sigma(m).at n=18A156099
• Semiprimes sp such that sp plus its digit sum is a perfect square.at n=26A244733
• Semiprimes of the form n*(3*n-1)/2.at n=20A245365
• Decimal representation of the diagonal from the corner to the origin of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 49", based on the 5-celled von Neumann neighborhood.at n=28A285558
• a(n) is the number of integer partitions of n for which the greatest part minus the least part is equal to the index of the seaweed algebra formed by the integer partition paired with its weight.at n=57A318176
• Semiprimes of the form p(6p - 1).at n=12A330409
• a(n) = n * Sum_{d|n} sigma(d)^3 / d.at n=11A344043
• The private keys for the 32 BTC Bitcoin puzzle.at n=14A369920
• Number of integer compositions of n whose leaders of strictly increasing runs are weakly increasing.at n=18A374690