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A104173 a(n) is the smallest integer equal to the sum and the product of the same n positive integers: a(n) = i(1) + i(2) + ... + i(n) = i(1)*i(2)*...*i(n). 5
1, 4, 6, 8, 8, 12, 12, 12, 15, 16, 16, 16, 18, 20, 24, 24, 24, 24, 24, 28, 27, 32, 30, 48, 32, 32, 32, 36, 36, 36, 42, 40, 40, 48, 48, 48, 45, 48, 48, 48, 48, 48, 54, 60, 54, 56, 54, 60, 63, 60, 60, 60, 63, 64, 64, 64, 64, 64, 70, 72, 72, 72, 72, 72, 72, 84, 80, 80, 81, 80, 80 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
a(n) <= 2n, since 1^(n-2)*2*n = (n-2)*1 + 2 + n. - Étienne Dupuis, Dec 07 2021
EXAMPLE
a(6)=12 because 6+2+1+1+1+1 = 6*2*1*1*1*1 = 12 is the smallest integer which is the sum and product of the same 6 positive integers.
MATHEMATICA
Table[k=1; While[Select[IntegerPartitions[k, {n}], Total@#==Times@@#&]=={}, k++]; k, {n, 71}] (* Giorgos Kalogeropoulos, Dec 07 2021 *)
CROSSREFS
Sequence in context: A079775 A247654 A262767 * A023991 A183005 A103189
KEYWORD
easy,nonn
AUTHOR
Louis Marmet (louis(AT)marmet.org), Mar 10 2005
STATUS
approved

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Last modified May 19 14:45 EDT 2024. Contains 372698 sequences. (Running on oeis4.)