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A098515 Least m such that m and m+n are both products of exactly n primes counting multiplicity. 4
1, 2, 4, 27, 36, 675, 810, 12393, 7552, 268992, 506240, 6436341, 2440692, 290698227, 455503986, 4897228800, 520575984, 519417147375, 124730265582, 8961777270765, 753891573760, 203558860750848, 51126160064490, 4021771417157632, 1305269217263592, 69131417822953472, 57710779788427264, 1838459534098563045, 63846774162325476 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
EXAMPLE
4=2*2 & 6=2*3; 27=3*3*3 & 30=2*3*5; 36=2*2*3*3 & 40=2*2*2*5; 675=3*3*3*5*5 & 680=2*2*2*5*17; 810=2*3*3*3*3*5 and 816=2*2*2*2*3*17; etc.
MATHEMATICA
f[n_Integer] := Plus @@ Transpose[FactorInteger[n]][[2]]; g[n_] := (k = 2^n; While[a = f[k]; b = f[k + n]; a != b || a != n, k++ ]; k); Do[ Print[ g[n]], {n, 12}]
CROSSREFS
Cf. A097978.
Sequence in context: A095182 A104465 A175759 * A256451 A059719 A264930
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Sep 11 2004
EXTENSIONS
More terms from David Wasserman, Feb 20 2008
STATUS
approved

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Last modified May 25 10:45 EDT 2024. Contains 372788 sequences. (Running on oeis4.)