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Search: id:A061595
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| A061595 |
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Product of digits + 1 is prime, sum of digits + 1 is prime and sum of digits - 1 is prime. |
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+0
1
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| 4, 6, 22, 66, 112, 114, 121, 123, 129, 132, 141, 147, 156, 165, 174, 189, 192, 198, 211, 213, 219, 231, 237, 273, 279, 291, 297, 312, 321, 327, 345, 354, 369, 372, 396, 411, 417, 435, 453, 459, 468, 471, 477, 486, 495, 516, 534, 543, 549, 561, 567, 576, 594
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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Harry J. Smith, Table of n, a(n) for n=1,...,1003
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EXAMPLE
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For 147 we have (1*4*7)+1=29, (1+4+7)+1=13, (1+4+7)-1=11.
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MAPLE
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a := proc (n) local nn: nn := convert(n, base, 10): if isprime(1+product(nn[j], j = 1 .. nops(nn))) = true and isprime(1+sum(nn[j], j = 1 .. nops(nn))) = true and isprime(-1+sum(nn[j], j = 1 .. nops(nn))) = true then n else end if end proc: seq(a(n), n = 1 .. 615); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 02 2009]
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PROGRAM
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(PARI) SumD(x)= { s=0; while (x>9, s=s+x-10*(x\10); x=x\10); return(s + x) } ProdD(x)= { p=1; while (x>9, p=p*(x-10*(x\10)); x=x\10); return(p*x) } { x=9; for (n=0, 1000, until(isprime(s+1) && isprime(s-1) && isprime(ProdD(x)+1), x++; s=SumD(x)); write("b061595.txt", n, " ", x) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Jul 25 2009]
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CROSSREFS
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Sequence in context: A101143 A083157 A151519 this_sequence A062940 A075813 A004032
Adjacent sequences: A061592 A061593 A061594 this_sequence A061596 A061597 A061598
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KEYWORD
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nonn,base
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AUTHOR
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Felice Russo (felice.russo(AT)katamail.com), May 22 2001
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EXTENSIONS
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Added 4 and 6 by Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 02 2009
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