cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A154506 Primes of the form concatenation(A141468(k), k).

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%I A154506 #15 Jul 14 2024 19:43:34
%S A154506 43,107,149,2719,3323,5641,5843,7253,7757,8059,8563,9067,12697,182141,
%T A154506 188147,224177,279221,298237,300239,315251,350281,360289,362291,
%U A154506 371299,388313,412333,418339,424343,448363,453367,460373,469379,473383,549449,558457
%N A154506 Primes of the form concatenation(A141468(k), k).
%e A154506 43 is a term since 43 is a prime and A141468(3)=4.
%e A154506 107 is a term since 107 is a prime and A141468(7)=10.
%p A154506 # read transforms; read b-file for A141468 (giving list b1); then:
%p A154506 t0:=[];
%p A154506 for n from 2 to nops(b1) do
%p A154506 t1:=cat(b1[n],n);
%p A154506 t2:=stoint(t1);
%p A154506 if isprime(t2) then t0:=[op(t0), t2]; fi;
%p A154506 od:
%p A154506 t0; # _N. J. A. Sloane_, Jun 27 2009
%Y A154506 Cf. A141468.
%K A154506 nonn,base
%O A154506 1,1
%A A154506 _Juri-Stepan Gerasimov_, Jan 11 2009
%E A154506 Edited and extended from a(13) onwards by _N. J. A. Sloane_, Jun 26 2009