login
a(n) = product prime(d + 1), where d ranges over all the decimal digits of n.
2

%I #41 May 12 2023 03:21:32

%S 2,3,5,7,11,13,17,19,23,29,6,9,15,21,33,39,51,57,69,87,10,15,25,35,55,

%T 65,85,95,115,145,14,21,35,49,77,91,119,133,161,203,22,33,55,77,121,

%U 143,187,209,253,319,26,39,65,91,143,169,221,247,299,377,34,51

%N a(n) = product prime(d + 1), where d ranges over all the decimal digits of n.

%H David A. Corneth, <a href="/A359802/b359802.txt">Table of n, a(n) for n = 0..10000</a>

%e a(0) = prime(0+1) = prime(1) = 2.

%e a(5) = prime(5+1) = prime(6) = 13.

%e a(20) = prime(2+1) * prime(0+1) = prime(3) * prime(1) = 5 * 2 = 10.

%p a:= n-> mul(ithprime(d+1), d=convert(n, base, 10)):

%p seq(a(n), n=0..171); # _Alois P. Heinz_, May 11 2023

%o (Python)

%o def a(n):

%o primes = (2, 3, 5, 7, 11, 13, 17, 19, 23, 29)

%o product = 1

%o for d in str(n):

%o product *= primes[int(d)]

%o return product

%o (PARI) a(n) = my(d=digits(n)); if (n==0, d=[0]); prod(k=1, #d, prime(d[k]+1)); \\ _Michel Marcus_, May 12 2023

%Y Very similar to A113581.

%Y Fixed points are in A115078.

%K nonn,easy,base

%O 0,1

%A _Fabian I. Garcia_, May 11 2023