A319955 a(1)=1; thereafter a(n+1) = a(n) + Product_{b=2..n+1} b^(1+floor(log_b(a(i)))).

1, 3, 39, 331815, 114126085737676800331815

Offset

1,2

Links

Table of n, a(n) for n=1..5.

Jeffrey Shallit, Automaticity IV: Sequences, sets, and diversity, J. Théor. Nombres Bordeaux 8.2 (1996): 347-367. See Theorem 10 p. 353, but b<=i+2 is a typo.

Prog

(PARI) a(n) = if (n==1, 1, a(n-1) + prod(b=2, n, b^(1+logint(a(n-1), b)))); \\ Michel Marcus, Jan 04 2021

Crossrefs

Sequence in context: A097421 A180418 A166999 * A317484 A196159 A084186

Adjacent sequences: A319952 A319953 A319954 * A319956 A319957 A319958

Keyword

nonn

Author

N. J. A. Sloane, Oct 04 2018

Extensions

Name corrected by Michel Marcus, Jan 04 2021

Status

approved