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A215477 Semiprimes with consecutive (ascending) digits. 2
4, 6, 9, 34, 123, 789, 901, 1234, 34567, 56789, 901234, 1234567, 7890123, 567890123, 12345678901, 345678901234567, 4567890123456789, 12345678901234567, 890123456789012345, 3456789012345678901, 456789012345678901234, 123456789012345678901234567, 1234567890123456789012345678901, 23456789012345678901234567890123 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

This is to semiprimes A001358 as A006055 is to primes A000040.

LINKS

Table of n, a(n) for n=1..24.

EXAMPLE

a(9) = 34567 because it is semiprime 13 * 2659, and (3,4,5,6,7) are consecutive ascending digits.

CROSSREFS

Cf. A001358, A118697, A059043, A006055, A161760.

Sequence in context: A190300 A081614 A192220 * A292154 A291717 A303699

Adjacent sequences:  A215474 A215475 A215476 * A215478 A215479 A215480

KEYWORD

nonn,base,easy

AUTHOR

Jonathan Vos Post, Aug 12 2012

EXTENSIONS

Corrected and extended by R. J. Mathar, Aug 13 2012

STATUS

approved

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Last modified February 27 15:16 EST 2020. Contains 332307 sequences. (Running on oeis4.)