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A106550 a(n) = n-th semiprime + (concatenation of its two factors, smallest factor first). 4
26, 29, 42, 35, 41, 50, 58, 233, 80, 239, 344, 251, 92, 257, 352, 269, 126, 368, 566, 376, 2, 87, 293, 578, 392, 311, 788, 323, 602, 329, 416, 804, 424, 341, 614, 359, 448, 638, 377, 836, 1232, 383, 464, 472, 852, 401, 488, 413, 1256, 674, 419, 686, 437, 512, 884 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..55.

FORMULA

a(n) = A001358(n) + A106554(n). - Reinhard Zumkeller, May 19 2005

EXAMPLE

First semiprime is 4; 4 is 2*2; 26=4+22.

Second semiprime is 6; 6 is 2*3; 29=6+23.

Third semiprime is 9; 9 is 3*3; 41=9+33.

Fourth semiprime is 10; 10 is 2*5; 35=10+25.

CROSSREFS

Cf. A084126, A084127, A001358.

Sequence in context: A256619 A055109 A106552 * A304949 A316617 A303815

Adjacent sequences:  A106547 A106548 A106549 * A106551 A106552 A106553

KEYWORD

base,easy,nonn

AUTHOR

Eric Angelini, May 09 2005

EXTENSIONS

More terms from Reinhard Zumkeller, May 19 2005

STATUS

approved

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Last modified October 27 23:01 EDT 2020. Contains 338045 sequences. (Running on oeis4.)