210925

Appears in sequences

• a(n) = n^4 - (n-1)^4 + (n-2)^4 - ... 0^4.at n=25A062392
• Doubly hexagonal numbers.at n=13A063249
• Triangular numbers with property that digits alternate in parity individually as well as in concatenation with previous terms.at n=25A068889
• Hexagonal numbers (A000384) in which parity of digits alternates.at n=26A297645
• Numbers that have exactly 8 representations as a k-gonal number, P(m,k) = m*((k-2)*m - (k-4))/2, k and m >= 3.at n=9A321158