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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

Table of n, a(n) for n=1..15.

L. C. Noll, Mersenne Prime Digits and Names.

Omar E. Pol, Determinacion geometrica de los numeros primos y perfectos.

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.)