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 A138816 Concatenation of initial digit of n-th Mersenne prime A000668(n), initial digit of n-th even superperfect number A061652(n) and initial digit of n-th perfect number A000396(n). 6
 326, 742, 314, 168, 843, 168, 521, 212, 212, 631, 181, 181, 632, 521, 155 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Also, concatenation of initial digit of n-th Mersenne prime A000668(n), initial digit of n-th superperfect number A019279(n) and initial digit of n-th perfect number A000396(n), if there are no odd superperfect numbers. Also, concatenation of A135613(n), A138124(n) and A135617(n). LINKS L. C. Noll, Mersenne Prime Digits and Names. CROSSREFS Cf. A000396, A000668, A019279, A061652, A135613, A135167, A138124, A138817. Sequence in context: A358148 A031516 A066128 * A138817 A158271 A203723 Adjacent sequences: A138813 A138814 A138815 * A138817 A138818 A138819 KEYWORD base,nonn,more AUTHOR Omar E. Pol, Apr 01 2008 EXTENSIONS a(13)-a(15) from Robert Price, Jun 16 2019 STATUS approved

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Last modified December 6 12:58 EST 2022. Contains 358634 sequences. (Running on oeis4.)