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A067087 Concatenation of n-th prime and its reverse. 7
22, 33, 55, 77, 1111, 1331, 1771, 1991, 2332, 2992, 3113, 3773, 4114, 4334, 4774, 5335, 5995, 6116, 6776, 7117, 7337, 7997, 8338, 8998, 9779, 101101, 103301, 107701, 109901, 113311, 127721, 131131, 137731, 139931, 149941, 151151, 157751 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Every term of the sequence is divisible by 11.
MATHEMATICA
Table[ ToExpression[ StringJoin[ ToString[Prime[n]], StringReverse[ ToString[ Prime[n]]]]], {n, 1, 40} ]
#*10^IntegerLength[#]+IntegerReverse[#]&/@Prime[Range[50]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Nov 11 2017 *)
PROG
(PARI) digitsIn(x)= { local(d); if (x==0, return(1)); d=1 + log(x)\log(10); if (10^d == x, d++, if (10^(d-1) > x, d--)); return(d) } Concat(a, b)= { return(a*10^digitsIn(b) + b) } Rev(x)= { local(d, r=0); while (x>0, d=x%10; x\=10; r=r*10 + d); return(r) } { for (n=1, 1000, p=prime(n); write("b067087.txt", n, " ", Concat(p, Rev(p))) ) } \\ Harry J. Smith, May 13 2010
CROSSREFS
Sequence in context: A116063 A131317 A176597 * A155709 A095044 A020151
KEYWORD
easy,nonn,base
AUTHOR
Amarnath Murthy, Jan 07 2002
EXTENSIONS
More terms from Robert G. Wilson v, Jan 09 2002
STATUS
approved

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Last modified June 14 20:28 EDT 2024. Contains 373401 sequences. (Running on oeis4.)