A115078 Numbers k such that k = prime(1 + d_1)*prime(1 + d_2)*...*prime(1 + d_m), where d_1 d_2 ... d_m is the decimal expansion of k.

171, 290, 2145, 3381, 74613, 10664845620, 14771330561681694, 2744819721528289762500

Offset: 1

Author

Giovanni Resta, Jan 12 2006

Keywords

• base
• nonn
• more

Comments

a(9), if it exists, must have more than 32 digits.

a(9) > 10^37 if it exists. - Chai Wah Wu, Aug 12 2017

Examples

			290 is a term because 290 = p(1+2)*p(1+9)*p(1+0) = 5*29*2.
		

Crossrefs

Cf. A097227.

Fixed points of A359802.

Programs

Mathematica

t={};Do[If[n==Times@@Prime[1+IntegerDigits@n], Print[n];AppendTo[t, n]], {n, 10^5}];t

PARI

is(n) = my(d=digits(n)); n==prod(i=1, #d, prime(1+d[i])) \\ Felix Fröhlich, Aug 12 2017