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).

326, 742, 314, 168, 843, 168, 521, 212, 212, 631, 181, 181, 632, 521, 155

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, A135617, 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