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A063275 Numbers that require three powerful numbers (definition 1) to sum to them. 3
3, 6, 11, 14, 19, 21, 22, 30, 38, 39, 42, 46, 47, 51, 55, 56, 60, 62, 66, 67, 69, 70, 71, 75, 77, 78, 79, 83, 84, 86, 92, 93, 94, 95, 102, 103, 105, 107, 110, 114, 115, 118, 120, 123, 131, 138, 139, 142, 143, 147, 151, 154, 156, 158, 159, 163, 165, 166, 167, 168, 175 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
The powerful numbers (A001694) start 1, 4, 8, 9, ... Now 11 = 1+1+9 and is not the sum of fewer terms, so 11 is in the sequence.
MATHEMATICA
With[{m = 200}, pow = Select[Range[m], # == 1 || Min[FactorInteger[#][[;; , 2]]] > 1 &]; s2 = Select[Union[Plus @@@ Tuples[pow, {2}]], # <= m &]; s3 = Select[Union[Plus @@@ Tuples[pow, {3}]], # <= m &]]; Complement[s3, pow, s2] (* Amiram Eldar, Feb 12 2023 *)
CROSSREFS
Sequence in context: A310094 A310095 A285422 * A191270 A182669 A026368
KEYWORD
nonn
AUTHOR
Jud McCranie, Jul 13 2001
EXTENSIONS
Offset corrected by Amiram Eldar, Feb 12 2023
STATUS
approved

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Last modified March 29 09:32 EDT 2024. Contains 371268 sequences. (Running on oeis4.)