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 A135613 Initial digit of Mersenne primes A000668. 6
 3, 7, 3, 1, 8, 1, 5, 2, 2, 6, 1, 1, 6, 5, 1, 1, 4, 2, 1, 2, 4, 3, 2, 4, 4, 4, 8, 5, 5, 5, 7, 1, 1, 4, 8, 6, 1, 4, 9, 1, 2, 1, 3, 1, 2, 1, 3 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..47. Landon Curt Noll, Mersenne Prime Digits and Names. FORMULA a(n) = A000030(A000668(n)). - Omar E. Pol, Jul 04 2019 EXAMPLE a(4)=1 because the 4th Mersenne prime A000668(4) is 127 and the initial digit of 127 is 1. MATHEMATICA lst = {* the list of terms in A000043 *}; f[n_] := Block[{pn = 2^n - 1}, Quotient[pn, 10^Floor[ Log[10, pn]] ]]; f@# & /@ lst (* Robert G. Wilson v, Apr 01 2008 *) IntegerDigits[#][[1]]&/@(2^#-1&/@MersennePrimeExponent[Range[47]]) (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 04 2019 *) CROSSREFS Cf. A000030, A000668, A077648, A080172. Sequence in context: A256978 A296442 A021272 * A019973 A010623 A283245 Adjacent sequences: A135610 A135611 A135612 * A135614 A135615 A135616 KEYWORD nonn,base,more AUTHOR Omar E. Pol, Mar 01 2008 EXTENSIONS More terms from Robert G. Wilson v, Apr 01 2008 a(40)-a(44) from David Radcliffe, Jan 21 2016 a(45)-a(47) from Ivan Panchenko, Apr 11 2018 STATUS approved

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Last modified June 17 18:36 EDT 2024. Contains 373463 sequences. (Running on oeis4.)