A155740 Odd numbers that are the concatenation of a prime p and the p-th nonprime nonnegative integer.

21, 1725, 1927, 2333, 3751, 79105, 83111, 131169, 167213, 173219, 191243, 193245, 197249, 227287, 229289, 251315, 269335, 307381, 317393, 367453, 379469, 383473, 397489, 419515, 421517, 431529, 433531, 439537, 449549, 463565, 499609, 521635

Offset

1,1

Links

Jinyuan Wang, Table of n, a(n) for n = 1..10000

Example

21 is a term because it is the concatenation of 2 (a prime) and the 2nd nonnegative nonprime integer 1 (which is odd);
1725 is a term because it is the concatenation of 17 (a prime) and the 17th nonnegative nonprime integer 25 (which is odd).

Maple

cat2 := proc(a, b) dgsb := max(1, ilog10(b)+1) ; a*10^dgsb+b ; end proc:
A155740 := proc(n) p := ithprime(n) ; c := A141468(p) ; if type(c, 'odd') then cat2(p, c) ; printf("%d, ", %) ; end if; return ; end proc:
seq(A155740(n), n=1..120) ; # R. J. Mathar, May 15 2010

Crossrefs

Cf. A000040, A141468.

Sequence in context: A130039 A221033 A221497 * A278776 A296597 A203327

Adjacent sequences: A155737 A155738 A155739 * A155741 A155742 A155743

Keyword

nonn,base,less

Author

Juri-Stepan Gerasimov, Jan 26 2009

Extensions

Corrected (1321 removed, all terms >= 200000 corrected) by R. J. Mathar, May 15 2010

Name and Example section edited by Jon E. Schoenfield, Feb 14 2019

Status

approved