A070229 - OEIS

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A070229

Next m>n such that m is divisible by lpf(n), lpf=A006530 largest prime factor.

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Or, for n>1, n + (largest prime divisor of n). [Anne Robinson, daughter of Herman P. Robinson, Oct 08 1981]

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

H. P. Robinson, Letter to N. J. A. Sloane, Oct 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.

Cf. A006530, A061228, A256393.

Iterations: A076271 (start=1), A036441 (start=2), A123581 (start=3).

Sequence in context: A115947 A247653 A061228 * A248835 A053568 A037225

Adjacent sequences: A070226 A070227 A070228 * A070230 A070231 A070232

KEYWORD

nonn,easy

AUTHOR

Reinhard Zumkeller, May 07 2002

STATUS

approved