28381

Appears in sequences

• Strong pseudoprimes to base 62.at n=24A020288
• 4-white numbers: partition digits of n^4 into blocks of 4 starting at right; sum of these 4-digit numbers equals n.at n=16A037044
• Composite numbers not divisible by 7 which in base 7 contain their largest proper factor as a substring.at n=7A063877
• Numbers n such that sigma (phi ( n ) ) = sigma (sigma (n ) ) where phi is Euler's totient and sigma is the multiplicative sum-of-divisors function.at n=14A065556
• a(n) = n^4 - 15*n + 15.at n=12A107253
• Capped binary boundary codes for holeless strictly non-overlapping polyhexes (all orientations and rotations included).at n=23A258002
• Capped binary boundary codes for fusenes (all orientations and rotations included).at n=23A258012
• Number of rooted trees with n nodes such that four equals the maximal number of subtrees of the same size extending from the same node.at n=12A318819
• Triangle read by rows: T(n,k) is the number of polygons formed by connecting the vertices of a regular {2*n+1}-gon such that they make k turns around the center point.at n=18A330660
• Positive integers whose binary form follows the periodic pattern 1101110: the concatenation of halftones 2 2 1 2 2 2 1, diminished by one, between successive pitches in the Ionian Major Scale.at n=14A371902
• Centered 30-gonal numbers.at n=43A389799