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A331464 Numbers k such that k and k + 1 are both binary Smith numbers (A278909). 3
1369, 1370, 1390, 1630, 1929, 2525, 2526, 2930, 3013, 3309, 3501, 3502, 3686, 3805, 3953, 3954, 4043, 4726, 4854, 5620, 5621, 5917, 6068, 6682, 6774, 6838, 7025, 7089, 7115, 7671, 7738, 7786, 8075, 9654, 9915, 10366, 10982, 11166, 11227, 11506, 11673, 11740, 11763 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

EXAMPLE

1369 is in the sequence since both 1369 and 1369 + 1 = 1370 are binary Smith numbers.

MATHEMATICA

binWt[n_] := Total @ IntegerDigits[n, 2]; binSmithQ[n_] := CompositeQ[n] && Plus @@ (Last@# * binWt[ First@# ] & /@ FactorInteger[n]) == binWt[n]; seq = {}; isSmith1 = binSmithQ[1]; Do[isSmith2 = binSmithQ[n]; If[isSmith1 && isSmith2, AppendTo[seq, n-1]]; isSmith1 = isSmith2, {n, 2, 12000}]; seq

CROSSREFS

Cf. A006753, A050219, A050220, A278909, A331463, A331465.

Sequence in context: A231268 A192823 A221932 * A167724 A156574 A145697

Adjacent sequences:  A331461 A331462 A331463 * A331465 A331466 A331467

KEYWORD

nonn,base

AUTHOR

Amiram Eldar, Jan 17 2020

STATUS

approved

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Last modified June 19 03:01 EDT 2021. Contains 345125 sequences. (Running on oeis4.)