A138818 Concatenation of initial digit of n-th even superperfect number A061652(n), initial digit of n-th Mersenne prime A000668(n) and initial digit of n-th perfect number A000396(n).

236, 472, 134, 618, 483, 618, 251, 122, 122, 361, 811, 811

Offset

1,1

Comments

Also, concatenation of initial digit of n-th superperfect number A019279(n), initial digit of n-th Mersenne prime A000668(n) and initial digit of n-th perfect number A000396(n), if there are no odd superperfect numbers.

Also, concatenation of A138124(n), A135613(n) and A135617(n).

Links

Table of n, a(n) for n=1..12.

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

J. M. Pedersen, Known Perfect Numbers.

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

Crossrefs

Cf. A000396, A000668, A019279, A061652, A135613, A135617, A138124, A138816, A138817, A138819, A138841, A138842, A138843.

Sequence in context: A244007 A218054 A235286 * A138819 A273181 A259639

Adjacent sequences: A138815 A138816 A138817 * A138819 A138820 A138821

Keyword

base,more,nonn,less

Author

Omar E. Pol, Apr 05 2008

Status

approved