121221

Appears in sequences

• Factorial expansions of the entries in A085216.at n=34A085218
• n expressed in Fibonacci binary-like number system using only 1's and 2's.at n=28A108960
• Numbers k such that k^p+p is prime, where p is product of the digits of k.at n=6A178327
• List of subwords (or factors) of the Thue-Morse "1,2"-word A001285.at n=39A214215
• List of words over {1,2} with equal numbers of 1's and 2's.at n=14A214218
• Elements of the Motzkin words sub-operad Motz of TN generated by 00 and 010.at n=29A231872
• Unique representation of nonnegative numbers by iterated tribonacci A, B and C sequences.at n=59A316713
• Number of nonnegative solutions to (x_1)^2 + (x_2)^2 + ... + (x_10)^2 <= n.at n=21A341405
• List of subwords (or factors) of the Kolakoski sequence (A000002).at n=41A376677