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A185300 Numbers k such that (sum of the decimal digits of k) + (product of the decimal digits of k) is prime. 2
1, 11, 12, 13, 15, 16, 18, 19, 20, 21, 23, 25, 27, 29, 30, 31, 32, 34, 35, 37, 43, 45, 50, 51, 52, 53, 54, 56, 57, 58, 59, 61, 65, 70, 72, 73, 75, 78, 79, 81, 85, 87, 89, 91, 92, 95, 97, 98, 101, 102, 104, 106, 110, 120, 140, 160, 200, 201, 203, 205, 209, 210, 223, 225, 230, 232 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..66.

EXAMPLE

236 is in the sequence because 2 + 3 + 6 + 2*3*6 = 11 + 36 = 47 is prime.

MAPLE

A007953 := proc(n) add(d, d=convert(n, base, 10)) ; end proc:

A007954 := proc(n) mul(d, d=convert(n, base, 10)) ; end proc:

isA185300 := proc(n) isprime(A007953(n)+A007954(n)) ; end proc:

for n from 1 to 300 do if isA185300(n) then printf("%a, ", n) ; end if; end do: # R. J. Mathar, Feb 08 2011

PROG

(MAGMA) [n: n in [1..232] | IsPrime(&+Intseq(n)+&*Intseq(n))]; // Bruno Berselli, Aug 02 2012

(PARI) is(n)=my(d=digits(n)); isprime(vecsum(d)+vecprod(d)) \\ Charles R Greathouse IV, Jun 06 2017

CROSSREFS

Cf. A007953, A007954.

Sequence in context: A138595 A192271 A214423 * A097932 A031300 A111019

Adjacent sequences:  A185297 A185298 A185299 * A185301 A185302 A185303

KEYWORD

nonn,base,easy

AUTHOR

Michel Lagneau, Feb 03 2011

STATUS

approved

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Last modified July 12 05:35 EDT 2020. Contains 335658 sequences. (Running on oeis4.)