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290 (two hundred [and] ninety) is the natural number following 289 and preceding 291.
|Cardinal||two hundred ninety|
(two hundred ninetieth)
|Factorization||2 × 5 × 29|
The product of three primes, 290 is a sphenic number, and the sum of four consecutive primes (67 + 71 + 73 + 79). The sum of the squares of the divisors of 17 is 290.
Not only is it a nontotient and a noncototient, it is also an untouchable number.
290 is the 16th member of the Mian–Chowla sequence; it can not be obtained as the sum of any two previous terms in the sequence.
See also the Bhargava–Hanke 290 theorem.
Integers from 291 to 299Edit
291 = 3·97, a semiprime, floor(3^14/2^14) (sequence A002379 in the OEIS).
292 = 22·73, a noncototient, untouchable number. The continued fraction representation of is [3; 7, 15, 1, 292, 1, 1, 1, 2...]; the convergent obtained by truncating before the surprisingly large term 292 yields the excellent rational approximation 355/113 to , repdigit in base 8 (444).
293 is prime, Sophie Germain prime, Chen prime, Irregular prime, Eisenstein prime with no imaginary part, and a strictly non-palindromic number.
294 = 2·3·72, the number of rooted trees with 28 vertices in which vertices at the same level have the same degree (sequence A003238 in the OEIS).
295 = 5·59, a centered tetrahedral number
296 = 23·37, a refactorable number, unique period in base 2, the number of regions formed by drawing the line segments connecting any two of the 12 perimeter points of an 2 times 4 grid of squares (illustration) (sequence A331452 in the OEIS), and the number of surface points on a 83 cube.
297 = 33·11, the number of integer partitions of 17, a decagonal number, and a Kaprekar number
298 = 2·149, is nontotient, noncototient, and the number of polynomial symmetric functions of matrix of order 6 under separate row and column permutations
299 = 13·23, a highly cototient number, a self number, and the twelfth cake number
- ^ "Sloane's A005282 : Mian-Chowla sequence". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-28.
- ^ Sloane, N. J. A. (ed.). "Sequence A005897". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ^ Sloane, N. J. A. (ed.). "Sequence A007716 (Number of polynomial symmetric functions of matrix of order n under separate row and column permutations)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.