A158054 a(1)=2, a(n+1) is the smallest prime > n*(sum of decimal digits of a(n)).

2, 3, 7, 23, 23, 29, 67, 97, 131, 47, 113, 59, 173, 149, 197, 257, 227, 191, 199, 367, 331, 149, 311, 127, 241, 179, 443, 307, 281, 331, 211, 127, 331, 233, 277, 563, 509, 521, 307, 397, 761, 577, 809, 733, 577, 857, 929, 941, 673, 787, 1103, 257, 733, 691, 877

Offset

1,1

Links

Table of n, a(n) for n=1..55.

Example

a(1)=2;
a(2)=3 > 2 = 1*2;
a(3)=7 > 6 = 2*3;
a(4)=23 > 21 = 3*7;
a(5)=23 > 20 = 4*(2+3);
a(6)=29 > 25 = 5*(2+3);
a(7)=67 > 66 = 6*(2+9);
a(8)=97 > 91 = 7*(6+7);
a(9)=131 > 128 = 8*(9+7);
a(10)=47 > 45 = 9*(1+3+1).

Maple

A007953 := proc(n) add(d, d=convert(n, base, 10)) ; end proc: A158054 := proc() option remember; if n = 1 then 2; else (n-1)*A007953(procname(n-1)) ; nextprime(%) ; end if; end proc: seq(A158054(n), n=1..120) ; # R. J. Mathar, May 19 2010

Crossrefs

Cf. A000027, A000040, A156615.

Sequence in context: A007660 A158055 A156615 * A134412 A005115 A113872

Adjacent sequences: A158051 A158052 A158053 * A158055 A158056 A158057

Keyword

nonn,base,easy

Author

Juri-Stepan Gerasimov, Mar 12 2009

Extensions

Corrected (193 replaced by 199, all terms from a(32) on replaced) by R. J. Mathar, May 19 2010

Edited by Jon E. Schoenfield, Feb 17 2019

Status

approved