290 (number)

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290 (two hundred [and] ninety) is the natural number following 289 and preceding 291.

In mathematics[edit]

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.^[1]

See also the Bhargava–Hanke 290 theorem.

In other fields[edit]

• "290" was the shipyard number of the CSS Alabama

See also the year 290.

Integers from 291 to 299[edit]

291[edit]

291 = 3·97, a semiprime, floor(3^14/2^14) (sequence A002379 in the OEIS).

292[edit]

292 = 2²·73, noncototient, untouchable number. The continued fraction representation of ${\displaystyle \pi }$ 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 ${\displaystyle \pi }$, repdigit in base 8 (444).

293[edit]

293 is prime, Sophie Germain prime, Chen prime, Irregular prime, Eisenstein prime with no imaginary part, strictly non-palindromic number. For 293 cells in cell biology, see HEK cell.

294[edit]

294 = 2·3·7², number of rooted trees with 28 vertices in which vertices at the same level have the same degree (sequence A003238 in the OEIS).

295[edit]

295 = 5·59, centered tetrahedral number, also the numerical designation of seven circumferential or half-circumferential routes of Interstate 95 in the United States.

296[edit]

296 = 2³·37, refactorable number, unique period in base 2, 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), number of surface points on a 8³ cube.^[2]

297[edit]

297 = 3³·11, number of integer partitions of 17, decagonal number, Kaprekar number

298[edit]

298 = 2·149, nontotient, noncototient, number of polynomial symmetric functions of matrix of order 6 under separate row and column permutations^[3]

299[edit]

299 = 13·23, highly cototient number, self number, the twelfth cake number

References[edit]