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A099068 Numbers n such that n=P(d_1)*P(d_2)*...*P(d_k)+(P(d_1)+P(d_2)+...+P(d_k)) where d_1 d_2 ... d_k is the decimal expansion of n and P(i) is the i-th prime. 2
23, 119, 428, 918, 1637682, 652827658771 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
There is no other term up to 15000000.
a(7) > 10^12. [Donovan Johnson, Mar 26 2010]
There are no other terms < 10^44. - Chai Wah Wu, Aug 12 2017
LINKS
C. Rivera, Puzzle 279The Prime Puzzles & Problems connection.
EXAMPLE
1637682 is in the sequence because 1637682=
P(1)*P(6)*P(3)*P(7)*P(6)*P(8)*P(2)+(P(1)+P(6)+P(3)+P(7)+P(6)+P(8)+P(2)).
MATHEMATICA
Do[h=IntegerDigits[n]; l=Length[h]; If[ !MemberQ[h, 0]&&n==Product[Prime[h[[k]]], {k, l}]+Sum[Prime[h[[k]]], {k, l}], Print[n]], {n, 15000000}]
CROSSREFS
Sequence in context: A367722 A293565 A362569 * A220408 A044355 A044736
KEYWORD
base,more,nonn
AUTHOR
Farideh Firoozbakht, Oct 29 2004
EXTENSIONS
Definition corrected by D. S. McNeil, Mar 14 2009
a(6) from Donovan Johnson, Mar 26 2010
STATUS
approved

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Last modified June 16 11:45 EDT 2024. Contains 373429 sequences. (Running on oeis4.)