A061597 - OEIS

A061597

Product of digits + 1 is prime, product of digits - 1 is prime, sum of digits + 1 is prime, sum of digits - 1 is prime and product of digits = sum of digits.

4, 6, 22, 123, 132, 213, 231, 312, 321, 111126, 111162, 111216, 111261, 111612, 111621, 112116, 112161, 112611, 116112, 116121, 116211, 121116, 121161, 121611, 126111, 161112, 161121, 161211, 162111, 211116, 211161, 211611, 216111, 261111, 611112

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..81

EXAMPLE

22 belong to the sequence because (2*2)+1=5, (2*2)-1=3, (2+2)+1=5, (2+2)-1=3 and 2+2=2*2.

PROG

(PARI) SumD(x)= s=0; while (x>9, s=s+x-10*(x\10); x=x\10); s + x

ProdD(x)=p=1; while (x>9, p=p*(x-10*(x\10)); x=x\10); p*x

x=9; for (n=0, 78, until(s==p && isprime(s+1) && isprime(s-1) && isprime(p+1) && isprime(p-1), x++; s=SumD(x); p=ProdD(x)); write("b061597.txt", n, " ", x)) \\ Harry J. Smith, Jul 25 2009; does not produce the terms 4 and 6

CROSSREFS

Sequence in context: A061595 A062940 A061596 * A075813 A107952 A004032

Adjacent sequences: A061594 A061595 A061596 * A061598 A061599 A061600

KEYWORD

nonn,base

AUTHOR

Felice Russo, May 22 2001

EXTENSIONS

4 and 6 added by Abdul Gaffar Khan, Nov 29 2015

STATUS

approved