26 = 1+7+5+7+6 and 263 = 17576
26 = 12 − 3 + 4 − 56 + 78 − 9
26 = 98 − 7 − 6 + 5 − 43 − 21
26 = 0^8 + 1^9 + 2^7 + 3^4 − 4^6 + 5^5 + 6^0 + 7^2 + 8^1 + 9^3
26 = 1^2 + 5^2
26 = (1 + 1) × (11 + 1 + 1)
= 22 + 2 + 2
= 33 − 3/3
= 4 + 44 × 4/(4 + 4) = 4!+ √4 + 4 - 4
= 5 × 5 + 5/5
= 6 × 6 − (66 − 6)/6
= 7 + 7 + (77 + 7)/7
= 8 + 8 + (88 − 8)/8
= 9 + 9 + 9 − 9/9
26 = 2 + 5 + 19 = 2 + 7 + 17 = 2 + 11 + 13, Sum of 3 distinct primes
Sum of four consecutive prime
Number k such that 10^(2*k+1) - 10^k - 1 is prime.
a(n) = n*(7*n + 11)/2 + 1.
Cake number, maximal number of pieces resulting from 5 planar cuts through a cube (or cake)
Number of distinct products i*j*k for 1 <= i <= j < k <= n, n = 6
Semiprime (Product of 2 Primes)
a(n) is the smallest semiprime such that difference between a(n) and next semiprime, b(n), is n, n = 7
Factors: 1, 2, 13, 26
Representations, Binary to Hexadecimal:
11010_2
222_3
122_4
101_5
42_6
35_7
32_8
28_9
24_11
22_12
20_13
1c_14
1b_15
1a_16
Undergraduate Texts in Mathematics
Graduate Studies in Mathematics
