A372848 Taxicab numbers that are sandwiched between semiprimes.

4104, 171288, 1728216, 2864288, 2987712, 2991816, 3512808, 3551112, 9016488, 10424232, 12753160, 13825728, 14197248, 36047592, 43450344, 43699392, 49844032, 63057960, 72131904, 75550088, 85188096, 92384712, 107872128, 107919000, 110808000, 117258678, 119824488, 132678000

Offset

1,1

Comments

All terms are even numbers.

Links

Table of n, a(n) for n=1..28.

Example

4104 = 2^3 * 3^3 * 19 (between 4103 = 11 * 373 and 4105 = 5 * 821).
171288 = 2^3 * 3^3 * 13 * 61 (between 171287 = 157 * 1091 and 171289 = 103 * 1663).
1728216 = 2^3 * 3^5 * 7 * 127 (between 1728215 = 5 * 345643 and 1728217 = 617 * 2801).

Mathematica

Select[Import["https://oeis.org/A001235/b001235.txt", "Table"][[;; , 2]], # < 1.5*10^8 && PrimeOmega[# + {-1, 1}] == {2, 2} &] (* Amiram Eldar, May 16 2024 *)

Crossrefs

Cf. A001235, A001358.

Subsequence of A371602.

Sequence in context: A346347 A227915 A371602 * A168345 A255158 A077188

Adjacent sequences: A372845 A372846 A372847 * A372849 A372850 A372851

Keyword

nonn

Author

Massimo Kofler, May 16 2024

Status

approved