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A111743 Numbers n such that the largest prime factor p of n is also the largest prime factor of n.p, where the dot means concatenation. 0
14, 24, 40, 56, 101, 103, 107, 109, 113, 127, 129, 130, 131, 134, 137, 139, 141, 142, 146, 149, 151, 157, 158, 159, 163, 166, 167, 170, 173, 177, 178, 179, 181, 183, 190, 191, 193, 194, 197, 199, 201, 202, 206, 211, 213, 214, 218, 219, 223, 226, 227, 229 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..52.

EXAMPLE

249 = 3*83; 24983 = 7*43*83; both numbers have the same largest prime factor, so 249 is in the sequence.

PROG

(MuPAD) for n from 2 to 500 do A := ifactor(n); b := A[nops(A)-1]; zi := trunc(log(10, b)+1); nn := n*10^zi+b; B := ifactor(nn); if A[nops(A)-1] = B[nops(B)-1] then print(n, b); end_if; end_for;

CROSSREFS

Sequence in context: A111455 A171124 A046290 * A164399 A164404 A211323

Adjacent sequences:  A111740 A111741 A111742 * A111744 A111745 A111746

KEYWORD

nonn,base

AUTHOR

Stefan Steinerberger, Nov 19 2005

EXTENSIONS

Edited by Charles R Greathouse IV, Apr 29 2010

STATUS

approved

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Last modified October 28 07:43 EDT 2021. Contains 348321 sequences. (Running on oeis4.)