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A115645 Powerful(1) numbers (A001694) that are sums of distinct factorials. 3
1, 8, 9, 25, 27, 32, 121, 128, 144, 729, 841, 864, 5041, 5184, 40328, 41067, 45369, 45387, 46208, 46225, 363609, 403225, 3674889, 43954688, 6230694987, 1401602635449 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Factorials 0! and 1! are not considered distinct.

LINKS

Table of n, a(n) for n=1..26.

Index entries for sequences related to powerful numbers

EXAMPLE

6230694987 = 13!+10!+8!+7!+4!+2!+1! = 3^3*11^2*1381^2.

MATHEMATICA

pwfQ[n_] := n==1 || Min[Last /@ FactorInteger@n] > 1; fac=Range[20]!; lst={}; Do[ n = Plus@@(fac*IntegerDigits[k, 2, 20]); If[pwfQ[n], AppendTo[lst, n]], {k, 2^20-1}]; lst

CROSSREFS

Cf. A001694, A025494, A115644, A115646, A089359.

Sequence in context: A032462 A077599 A109097 * A068435 A302554 A124438

Adjacent sequences:  A115642 A115643 A115644 * A115646 A115647 A115648

KEYWORD

nonn

AUTHOR

Giovanni Resta, Jan 27 2006

STATUS

approved

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Last modified September 22 12:52 EDT 2019. Contains 327307 sequences. (Running on oeis4.)