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A070229
Next m>n such that m is divisible by lpf(n), lpf=A006530 largest prime factor.
14
2, 4, 6, 6, 10, 9, 14, 10, 12, 15, 22, 15, 26, 21, 20, 18, 34, 21, 38, 25, 28, 33, 46, 27, 30, 39, 30, 35, 58, 35, 62, 34, 44, 51, 42, 39, 74, 57, 52, 45, 82, 49, 86, 55, 50, 69, 94, 51, 56, 55, 68, 65, 106, 57, 66, 63, 76, 87, 118, 65, 122
OFFSET
1,1
COMMENTS
Or, for n>1, n + (largest prime divisor of n). [Anne Robinson, daughter of Herman P. Robinson, Oct 08 1981]
FORMULA
a(n) = (n/lpf(n)+1)*lpf(n).
a(n) = n+lpf(n) where lpf=A006530 largest prime factor. For example, a(14)=14+7=21 (instead of ((14/7)+1)*7). - Philippe Lallouet (philip.lallouet(AT)wanadoo.fr), Jun 14 2007
MATHEMATICA
Table[n + Last@(First/@FactorInteger[n]), {n, 70}] (* Vladimir Joseph Stephan Orlovsky, Apr 08 2011 *)
PROG
(Haskell)
a070229 n = n + a006530 n
-- Reinhard Zumkeller, Nov 08 2015, Nov 14 2011
(PARI) vector(100, n, if(n>1, vecmax(factor(n)[, 1]), 1) + n) \\ Altug Alkan, Nov 13 2015
CROSSREFS
Cf. A036441.
Iterations: A076271 (start=1), A036441 (start=2), A123581 (start=3).
Sequence in context: A115947 A247653 A061228 * A248835 A053568 A037225
KEYWORD
nonn,easy
AUTHOR
Reinhard Zumkeller, May 07 2002
STATUS
approved