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 A256076 Non-palindromic balanced primes. 7
 1823, 1933, 2141, 2251, 2633, 2963, 3061, 3391, 4091, 4253, 4363, 4583, 5393, 5717, 5827, 6637, 6857, 6967, 7829, 8147, 8419, 8969, 9067, 9397, 14303, 14503, 15013, 15313, 15413, 15913, 16223, 16823, 17033, 17333, 18043, 18143, 18443, 18743, 19553, 19753, 19853 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Here a number is called balanced if the sum of digits weighted by their arithmetic distance from the "center" is zero. Palindromic primes (A002385) are "trivially" balanced, so they are excluded here. These are the primes in A256075, see there for further information. See A256081 for the binary version and A256090 for the hexadecimal version. LINKS Robert Israel, Table of n, a(n) for n = 1..10000 EXAMPLE a(1)=1823 is balanced because 1*3/2 + 8*1/2 = 2*1/2 + 3*3/2. MAPLE filter:= proc(n) local L, m; L:= convert(n, base, 10); m:= (1+nops(L))/2; add(L[i]*(i-m), i=1..nops(L))=0 and isprime(n) and L <> ListTools:-Reverse(L) end proc: select(filter, [seq(i, i=1001..20000, 2)]); # Robert Israel, May 29 2018 PROG (PARI) is(n, d=digits(n), o=(#d+1)/2)=!(vector(#d, i, i-o)*d~)&&d!=Vecrev(d)&&isprime(n) CROSSREFS Cf. A256075, A256081, A256090, A002385. Sequence in context: A174770 A218104 A171349 * A179581 A230052 A234222 Adjacent sequences: A256073 A256074 A256075 * A256077 A256078 A256079 KEYWORD nonn,base AUTHOR Eric Angelini and M. F. Hasler, Mar 14 2015 STATUS approved

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Last modified September 10 00:26 EDT 2024. Contains 375769 sequences. (Running on oeis4.)