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A046466 Concatenation of numbers from 1 to a(n) has exactly 7 prime factors, with multiplicity. 0
28, 30, 42, 44, 46 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..4.

P. De Geest, Normal Smarandache Concatenated Numbers, Prime factors from 1 up to n

C. Rivera, Primes by Listing

M. Fleuren, Smarandache Factors and Reverse factors

CROSSREFS

Cf. A046460.

Sequence in context: A042621 A042622 A044977 * A054396 A083274 A067913

Adjacent sequences:  A046463 A046464 A046465 * A046467 A046468 A046469

KEYWORD

nonn,hard,base

AUTHOR

Patrick De Geest, Aug 15 1998.

STATUS

approved

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Last modified September 22 17:05 EDT 2018. Contains 315270 sequences. (Running on oeis4.)