990100

Appears in sequences

• Numbers, with an even number of digits, that are the sum of the squares of their two halves (leading zeros allowed only for the second half).at n=2A055616
• a(n)= A*10^(3*n)+B with A=(10^(3*n)-10^n) and B=10^(2*n).at n=0A055617
• a(n) = A*10^(4*n-1) + B with A = 990*(10^(4*n)-1)/9999 and B = 990000*(10^(4*n-4)-1)/9999 + 100.at n=0A055618
• Decimal numbers n such that after possibly prefixing leading 0's to n, the resulting number n' can be broken into 2 numbers of equal length, n' = xy, such that x^2+y^2 = n (y may also have leading zeros).at n=4A064942
• Decimal numbers n such that after possibly prefixing a leading 0 to n, the resulting number n' can be broken into 2 strings of the same length, n' = xy, such that x^2+y^2 = n.at n=4A101311
• Numbers k such that k*(k+3) gives the concatenation of a number m with itself.at n=12A116287
• Numbers k with the property that there exist nonnegative integers a and b such that k = concat(a,b) = a^2+b^2.at n=7A178530
• Positive integers of the form x*10^k + y which also equal x^2 + y^2 (x, y and k being positive integers).at n=5A275986
• Numbers k whose decimal expansion can be split into two parts s and t with k = s^2 + t^2.at n=4A368416