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A037278 Replace n by concatenation of its divisors. 28
1, 12, 13, 124, 15, 1236, 17, 1248, 139, 12510, 111, 1234612, 113, 12714, 13515, 124816, 117, 1236918, 119, 12451020, 13721, 121122, 123, 1234681224, 1525, 121326, 13927, 12471428, 129, 12356101530, 131, 12481632, 131133, 121734 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) is union of A176555(n) for n >= 1 and A176556(n) for n >= 2. See A176553 (numbers m such that concatenations of divisors of m are noncomposites) and A176554 (numbers m such that concatenations of divisors of m are nonprimes). [From Jaroslav Krizek, Apr 21 2010]

a(n) = concatenation of n-th row of the triangle in A027750.

LINKS

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

MATHEMATICA

a[n_] := ToExpression[ StringJoin[ ToString /@ Divisors[n] ] ]; Table[ a[n], {n, 1, 34}] (* Jean-Fran├žois Alcover, Dec 01 2011 *)

FromDigits[Flatten[IntegerDigits/@Divisors[#]]]&/@Range[40] (* Harvey P. Dale, Nov 09 2012 *)

PROG

(Haskell)

a037278 = read . concatMap show . a027750_row :: Integer -> Integer

-- Reinhard Zumkeller, Jul 13 2013, May 01 2012, Aug 07 2011

CROSSREFS

Cf. A027750, A037283, A037277, A106708.

Sequence in context: A064003 A135123 A129476 * A164852 A033048 A108771

Adjacent sequences:  A037275 A037276 A037277 * A037279 A037280 A037281

KEYWORD

nonn,easy,base,nice

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Erich Friedman.

STATUS

approved

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Last modified April 17 20:01 EDT 2014. Contains 240655 sequences.