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A331465 a(n) begins the first run of exactly n consecutive binary Smith numbers (A278909). 1
15, 1390, 1369, 11763, 47802, 1529690, 4628217, 1544053, 804607562, 4747704789 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
a(11) > 5*10^10.
LINKS
EXAMPLE
a(2) = 1390 since 1390 and 1391 are binary Smith numbers.
a(3) = 1369 since 1369, 1370, and 1371 are binary Smith numbers.
MATHEMATICA
binWt[n_] := Total@IntegerDigits[n, 2]; binSmithQ[n_] := CompositeQ[n] && Plus @@ (Last@# * binWt[ First@# ] & /@ FactorInteger[n]) == binWt[n]; n = 1; count = 0; max = 6; seq = Table[0, {max}]; While[count < max, n1 = n; If[binSmithQ[n], While[binSmithQ[++n1]]; d = n1 - n; If[d <= max && seq[[d]] == 0, count++; seq[[d]] = n]]; n = n1 + 1]; seq
CROSSREFS
Sequence in context: A071972 A350994 A206376 * A223058 A200994 A338634
KEYWORD
nonn,base,more
AUTHOR
Amiram Eldar, Jan 17 2020
STATUS
approved

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Last modified March 28 15:28 EDT 2024. Contains 371254 sequences. (Running on oeis4.)