4004001

Appears in sequences

• Squares composed of digits {0,1,4}, not ending with zero.at n=9A058414
• Squares such that each digit is a square and the sum of the digits is a square.at n=22A061270
• a(1) = 1; a(n+1) = smallest square > a(n) with leading digit equal to final digit of a(n) and final digit not 0.at n=12A061449
• Largest n-digit square which leaves a square at every step if most significant digit and least significant digit are deleted until a one- or two-digit square is obtained. a(2n) = 0 if no such square exists. a(2n+1) = 9*10^2n only if no nontrivial candidate exists.at n=6A077486
• Squares which leave a square at every step if most significant digit and least significant digit are deleted until a one-digit or two-digit square is obtained.at n=35A077487
• a(n+1) is the smallest square > a(n) such that every concatenation (n > 1) is a prime.at n=15A087352
• a(n) = A129967(n) with digits reversed.at n=38A129970
• Squares k that are not divisible by 10, and whose reverse and digit sum are also squares, such that the digit sum divides both k and its reverse.at n=12A354078