A307507 Brazilian semiprimes.

10, 14, 15, 21, 22, 26, 33, 34, 35, 38, 39, 46, 51, 55, 57, 58, 62, 65, 69, 74, 77, 82, 85, 86, 87, 91, 93, 94, 95, 106, 111, 115, 118, 119, 121, 122, 123, 129, 133, 134, 141, 142, 143, 145, 146, 155, 158, 159, 161, 166, 177, 178, 183, 185, 187, 194, 201, 202, 203, 205, 206, 209, 213, 214, 215, 217, 218

Offset

1,1

Comments

Comparison with A001358 (semiprimes): in this sequence, there are no squared primes apart from 121 = (11111)_3, and also 6 is missing from here since it is not Brazilian.

Different from the squarefree semiprimes of A006881: this sequence = {A006881 \ 6} Union {121}.

Links

Table of n, a(n) for n=1..67.

Example

a(20) = 74 = 2 * 37 = (22)_36 is semiprime and Brazilian.
25 = 5 * 5 is semiprime and no Brazilian, and 45 = (55)_8 = (33)_14 = 3^2 * 5 is Brazilian but no semiprime.

Crossrefs

Intersection of A001358 and A125134.

Cf. A006881, A190300, A196104.

Sequence in context: A366413 A367018 A087247 * A171156 A235690 A271568

Adjacent sequences: A307504 A307505 A307506 * A307508 A307509 A307510

Keyword

nonn,base

Author

Bernard Schott, Apr 11 2019

Status

approved