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A119729 Semiprimes where final digit of each value is initial digit of next value. 0
4, 46, 6, 62, 21, 14, 49, 9, 91, 15, 51, 106, 65, 55, 57, 74, 403, 33, 34, 407, 77, 703, 35, 58, 82, 22, 25, 501, 111, 115, 502, 26, 69, 93, 38, 85, 505, 511, 118, 86, 611, 119, 94, 411, 121, 122, 201, 123, 39, 95, 514, 413, 301, 129, 901, 133, 302, 202, 203, 303, 305 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

There are a countably infinite number of such sequences; this is the one in base 10 starting with A001358(1) = 4. It is a permutation of the semiprimes not ending in 0. See also A010879 Final digit of n; A000030 Initial digit of n.

LINKS

Table of n, a(n) for n=1..61.

FORMULA

a(1) = 4. a(n+1) = least element of A001358 for which A000030(a(n+1) =/= 0 and not previously appearing in this sequence, such that a(n) mod 10 = A000030(a(n+1)). a(n+1) = least element of A001358 with nonzero final digit and not previously appearing in this sequence, such that final digit of a(n) = initial digit of a(n+1).

CROSSREFS

Cf. A000030, A001358, A010879.

Sequence in context: A288554 A288562 A222899 * A134110 A176312 A309450

Adjacent sequences:  A119726 A119727 A119728 * A119730 A119731 A119732

KEYWORD

base,easy,nonn

AUTHOR

Jonathan Vos Post, Jun 14 2006

STATUS

approved

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Last modified January 19 12:52 EST 2020. Contains 331049 sequences. (Running on oeis4.)