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A368402
Numbers k such that k and k+1 are both in A268375.
3
1, 2, 3, 4, 7, 8, 11, 12, 16, 17, 18, 19, 27, 28, 31, 43, 44, 47, 48, 49, 52, 63, 67, 75, 79, 80, 97, 98, 112, 116, 124, 127, 147, 148, 162, 163, 171, 172, 175, 191, 192, 207, 211, 241, 242, 243, 244, 256, 268, 271, 283, 288, 292, 316, 324, 331, 332, 337, 367
OFFSET
1,2
COMMENTS
Analogous to A342028, as A268375 is analogous to A130091.
The Mersenne primes (A000668) are terms.
LINKS
MATHEMATICA
f[e_] := Position[Reverse[IntegerDigits[e, 2]], 1] // Flatten; q[n_] := q[n] = UnsameQ @@ Flatten[f /@ FactorInteger[n][[;; , 2]]]; Select[Range[100], q[#] && q[#+1] &]
PROG
(PARI) isA268375(n) = {my(e = factor(n)[, 2], b = 0); for(i=1, #e, b = bitor(b, e[i])); n == 1 || b == vecsum(e); }
lista(kmax) = {my(is1 = 0, is2); for(k = 1, kmax, is2 = isA268375(k); if(is1 && is2, print1(k-1, ", ")); is1 = is2); }
CROSSREFS
Subsequence of A130091, A268375 and A342028.
Subsequences: A000668, A368403, A368404.
Sequence in context: A026808 A240767 A342028 * A284937 A271441 A328421
KEYWORD
nonn,base
AUTHOR
Amiram Eldar, Dec 23 2023
STATUS
approved