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A068845 Final digits of the smallest prime starting with n!. 2
1, 3, 1, 1, 1, 7, 1, 29, 17, 43, 29, 13, 47, 19, 73, 37, 19, 41, 31, 41, 31, 1, 1, 37, 31, 37, 59, 41, 53, 41, 47, 1, 1, 89, 37, 53, 73, 1, 1, 43, 151, 1, 47, 1, 509, 127, 71, 167, 67, 167, 149, 67, 61, 139, 67, 59, 107, 241, 1, 61, 1, 149, 293, 127, 71, 151, 337, 107, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n)= 1 or a(n) >= the smallest prime larger than n. Conjecture: The terms are noncomposite numbers. Motivation: a composite number not coprime to n! cannot be a member.

REFERENCES

Amarnath Murthy, Smarandache Reciprocal function and an elementary inequality. Smarandache Notions Journal, Vol. 1-2-3, Spring 2000.

LINKS

Table of n, a(n) for n=1..69.

EXAMPLE

a(7) = 11 because the smallest prime starting with 7! = 5040 is 504011 and so the last digits are 11.

MAPLE

for i from 1 to 70 do a := nextprime(i!*10); b := 1; while(a-i!*10^b>=10^b) do b := b+1; a := nextprime(i!*10^b); end do; c[i] := a-i!*10^b; end do:q := seq(c[i], i=1..70);

MATHEMATICA

Table[p = i!; k = 1; While[IntegerDigits[p] != Take[IntegerDigits[x = NextPrime[y = p*10^k]], IntegerLength[p]], k += 1]; x - y, {i, 69}] (* Jayanta Basu, Aug 09 2013 *)

CROSSREFS

Cf. A068844.

Sequence in context: A293682 A276651 A185587 * A324910 A257100 A152884

Adjacent sequences:  A068842 A068843 A068844 * A068846 A068847 A068848

KEYWORD

nonn,base

AUTHOR

Amarnath Murthy, Mar 10 2002

EXTENSIONS

More terms from Sascha Kurz, Mar 17 2002

STATUS

approved

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Last modified October 21 01:18 EDT 2019. Contains 328291 sequences. (Running on oeis4.)