proposed

approved

editing

proposed

Harry J. Smith, <a href="/A066027/b066027.txt">Table of n, a(n) for n = 1,...,1000</a>

a(11)=112 because 1 + 1 + 2 = 4 and , 2*1*1 = 2 , and 4 - 2 =2 and 2 , which is prime. [corrected by _Harry J. Smith_, Nov 07 2009]

(PARI) ProdD(x)= { local(p=1); while (x>9 && p>0, p*=x%10; x\=10); return(p*x) } SumD(x)= { local(s=0); while (x>9, s+=x%10; x\=10); return(s + x) } { n=0; for (m=1, 10^9, if (isprime(SumD(m) - ProdD(m)), write("b066027.txt", n++, " ", m); if (n==1000, return)) ) } [From _\\ _Harry J. Smith_, Nov 07 2009]

EXAMPLE corrected by Harry J. Smith, Nov 07 2009

approved

editing

_Enoch Haga (Enokh(AT)comcast.net), _, Dec 11 2001

(PARI) ProdD(x)= { local(p=1); while (x>9 && p>0, p*=x%10; x\=10); return(p*x) } SumD(x)= { local(s=0); while (x>9, s+=x%10; x\=10); return(s + x) } { n=0; for (m=1, 10^9, if (isprime(SumD(m) - ProdD(m)), write("b066027.txt", n++, " ", m); if (n==1000, return)) ) } [From _Harry J. Smith (hjsmithh(AT)sbcglobal.net), _, Nov 07 2009]

EXAMPLE corrected by _Harry J. Smith (hjsmithh(AT)sbcglobal.net), _, Nov 07 2009

Harry J. Smith, <a href="/A066027/b066027.txt">Table of n, a(n) for n=1,...,1000</a>

easy,nonn,base,new

Harry J. Smith, <a href="b066027.txt">Table of n, a(n) for n=1,...,1000</a>

a(1011)=112 because 1+1+2=4 and 2*1*1=2 and 4-2=2 and 2 is prime

(PARI) ProdD(x)= { local(p=1); while (x>9 && p>0, p*=x%10; x\=10); return(p*x) } SumD(x)= { local(s=0); while (x>9, s+=x%10; x\=10); return(s + x) } { n=0; for (m=1, 10^9, if (isprime(SumD(m) - ProdD(m)), write("b066027.txt", n++, " ", m); if (n==1000, return)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Nov 07 2009]

easy,nonn,base,new

EXAMPLE corrected by Harry J. Smith (hjsmithh(AT)sbcglobal.net), Nov 07 2009

a(10)=112 because 1+1+2=4 and 2*1*1=2, and 4-2=2, and 2 is prime

easy,nonn,base,new

easy,nonn,base,new

Enoch Haga (Enokh(AT)aolcomcast.comnet), Dec 11 2001

Sum of digits of n minus product of digits of n is prime.

20, 30, 50, 70, 101, 102, 104, 106, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 131, 140, 141, 151, 160, 161, 171, 181, 191, 200, 201, 203, 205, 209, 210, 211, 230, 250, 290, 300, 302, 304, 308, 311, 320, 340, 380, 401, 403, 407, 409, 410

1,1

a(10)=112 because 1+1+2=4 and 2*1*1=2, and 4-2=2, and 2 is prime

Cf. A066024, A038369.

easy,nonn,base

Enoch Haga (Enokh(AT)aol.com), Dec 11 2001

approved