A363790 - OEIS

A363790

Numbers k such that k and k+1 are both primitive binary Niven numbers (A363787).

115, 155, 204, 284, 355, 395, 404, 555, 564, 595, 675, 804, 835, 846, 1075, 1124, 1164, 1182, 1266, 1315, 1434, 1555, 1604, 1686, 1795, 1938, 2075, 2124, 2195, 2244, 2315, 2324, 2358, 2435, 2595, 3084, 3204, 3282, 3366, 4124, 4195, 4206, 4235, 4244, 4364, 4458

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

EXAMPLE

115 is a term since 115 and 116 are both primitive binary Niven numbers.

MATHEMATICA

binNivQ[n_] := Divisible[n, DigitCount[n, 2, 1]]; q[n_] := binNivQ[n] && ! (EvenQ[n] && binNivQ[n/2]); Select[Range[5000], q[#] && q[# + 1] &]

PROG

(PARI) isbinniv(n) = !(n % hammingweight(n));

isprim(n) = isbinniv(n) && !(!(n%2) && isbinniv(n/2));

is(n) = isprim(n) && isprim(n+1);

CROSSREFS

Subsequence of A049445, A330931 and A363787.

Subsequences: A363791, A363792.

Sequence in context: A129544 A095621 A051975 * A183626 A224673 A181931

Adjacent sequences: A363787 A363788 A363789 * A363791 A363792 A363793

KEYWORD

nonn,base

AUTHOR

Amiram Eldar, Jun 22 2023

STATUS

approved