A244548 Palindromes n with nonzero digits such that n +/- the product of digits of n are both palindromes.
1, 2, 3, 4, 252, 15451, 25152, 25252, 25352, 25452, 36563, 51415, 52125, 52225, 52325, 52425, 63536, 92529, 1455541, 1545451, 1954591, 2255522, 2525252, 2853582, 2856582, 3354533, 3534353, 4155514, 4453544, 4456544, 4515154, 4543454, 4546454, 5145415, 5225225, 5334335, 5415145
Offset: 1
Examples
252 has all digits > 0. 252 is a palindrome, 252 - 2*5*2 = 232 is a palindrome, and 252 + 2*5*2 = 272 is a palindrome. Thus 252 is a member of this sequence.
Programs
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PARI
rev(n)={r="";for(i=1,#digits(n),r=concat(Str(digits(n)[i]),r));return(eval(r))} for(n=1,10^7,if(rev(n)==n,dig=digits(n);p=prod(k=1,#dig,dig[k]);if(p!=0,mi=n-p;ma=n+p;if(rev(mi)==mi&&rev(ma)==ma,print1(n,", ")))))
Comments