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A120825 Number of digits of primes with n consecutive digits ascending beginning with the digit seven. 8
1, 5, 15, 51 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Digits are in ascending order beginning with 7 and after 9 comes 0.

The sequence "Primes with n consecutive digits descending beginning with the digit seven" has only two terms below 6001, namely 1 and 5, which represent the primes 7 and 76543, respectively.

LINKS

Table of n, a(n) for n=1..4.

EXAMPLE

1 is here because 7 is prime.

5 is here because 78901 is prime.

15 is here because 789012345678901 is a prime.

51 is here because 789012345678901234567890123456789012345678901234567 is prime.

MATHEMATICA

fQ[n_] := PrimeQ@ FromDigits@ Mod[6+Range@n, 10]; lst = {}; Do[ If[fQ@n, AppendTo[lst, n]; Print@n], {n, 5000}]; lst

CROSSREFS

Cf. A006055, A120819, A120820, A120821, A120822, A120823, A120824, A120826, A120827.

Sequence in context: A034539 A029609 A014274 * A199985 A255442 A149576

Adjacent sequences:  A120822 A120823 A120824 * A120826 A120827 A120828

KEYWORD

base,hard,nonn

AUTHOR

Robert G. Wilson v, Jul 05 2006

STATUS

approved

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Last modified November 13 17:34 EST 2019. Contains 329106 sequences. (Running on oeis4.)