396 = 26 + 46 + 76 + 146 + 166 + 266 + 266 + 306 + 326 + 326
39 = 1344763 + 1173673 + (-159380)3
39 = 123 × 4 + 5 + 6 + 7 + 8 + 9
39 = 98 − 76 − 5 + 43 − 21
39 = 0^6 + 1^8 − 2^9 − 3^7 + 4^5 + 5^0 + 6^4 + 7^3 + 8^2 + 9^1
39 = (1 + 1 + 1) × (11 + 1 + 1)
= 2 × (22 − 2) − 2/2
= 3 + 3 + 33
= 44 − 4 − 4/4
= 55 − 5 − 55/5
= 6 + 6 × 66/(6 + 6)
= 7 × 7 − (77 − 7)/7
= 8 × 8 − 8 − 8 − 8 − 8/8
= 9 + 9 + 9 + (99 + 9)/9
Number k such that k^2 + 2 is prime (1523)
Number k such that (7*10^k + 71)/3 is prime.
Sums of four consecutive primes.
Smallest number of multiplicative persistence 3
Smallest number whose sum of digits is 12.
Semiprime (Product of 2 Primes)
Semiprime s such that s-/+2 are primes.
39 cannot be written as a sum of 3 squares. (Integers that are not a sum of three squares)
Factors: 1, 3, 13, 39
Representations, Binary to Hexadecimal:
100111_2
1110_3
213_4
124_5
103_6
54_7
47_8
43_9
36_11
33_12
30_13
2b_14
29_15
27_16
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Undergraduate Texts in Mathematics
Graduate Studies in Mathematics
