A080172 Final digit of n-th Mersenne prime A000668(n).

3, 7, 1, 7, 1, 1, 7, 7, 1, 1, 7, 7, 1, 7, 7, 7, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 1, 7, 7, 1, 7, 7, 1, 7, 1, 1, 1, 1, 1, 7, 7, 7, 1, 1, 7, 1, 1

Offset

1,1

Comments

Distribution of final digit for Mersenne primes appears (naturally) to be different from distribution for regular primes. Unconfirmed 48th digit in sequence is 1 (awaiting confirmation of 48th Mersenne prime).

References

G. H. Hardy and E. M. Wright, An Introduction to the Theory of Numbers. 3rd ed., Oxford Univ. Press, 1954, p. 16.

Links

Table of n, a(n) for n=1..47.

Great Internet Mersenne Prime Search (GIMPS), Distributed Computing Projects

Mersenne Primes, History, Theorems and Lists

Maple

(Maple code from N. J. A. Sloane) # let s1 := list of terms in A000043
f:=n->if n mod 4 = 0 then 4 else n mod 4; fi; map(x->2^f(x)-1, s1);

Mathematica

Mod[2^MersennePrimeExponent[Range[47]]-1, 10] (* Harvey P. Dale, Aug 09 2023 *)

Crossrefs

Cf. A000668, A007652, A080173.

Sequence in context: A019806 A199589 A354977 * A133065 A335815 A021733

Adjacent sequences: A080169 A080170 A080171 * A080173 A080174 A080175

Keyword

base,more,nonn

Author

Mark Dowdeswell (mark(AT)stats.wits.ac.za), Feb 04 2003

Extensions

Updated by N. J. A. Sloane, Apr 01 2008

a(40)-a(47) from Ivan Panchenko, Apr 11 2018

Status

approved