A226092
Fourth powers that become prime when their most significant (leftmost) decimal digit is removed.
Original entry on oeis.org
2401, 279841, 15752961, 20151121, 35153041, 43046721, 62742241, 68574961, 88529281, 200533921, 260144641, 547981281, 671898241, 2385443281, 2655237841, 2750058481, 2847396321, 3262808641, 3722098081, 4640470641, 5887339441, 6414247921, 8428892481, 8882874001
Offset: 1
a(1) = 7^4 = 2401, because removing the leftmost digit (4) leaves 401, which is prime.
a(2) = 23^4 = 279841, because removing the leftmost digit (2) leaves 79841, which is prime.
a(3) = 63^4 = 15752961, because removing the leftmost digit (1) leaves 5752961, which is prime.
a(10) = 119^4 = 200533921, because removing the leftmost digit (2) leaves 00533921 = 533921, which is prime.
A226531
Cubes that become prime when their least-significant (rightmost) digit is removed.
Original entry on oeis.org
27, 3375, 4096, 4913, 35937, 97336, 110592, 148877, 421875, 681472, 1191016, 1442897, 1560896, 2628072, 3241792, 3581577, 3869893, 4741632, 5359375, 8998912, 10218313, 12649337, 16777216, 16974593, 21253933, 26730899, 31255875, 32157432, 43986977, 45882712
Offset: 1
4096 = 16^3, and becomes the prime number 409 when truncated.
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Select[Range[1000]^3,PrimeQ[Floor[#/10]]&] (* Harvey P. Dale, May 28 2021 *)
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library(gmp)trimR=function(x) { x=as.character(x); ifelse(nchar(x)<2,0,substr(x,1,nchar(x)-1)) }
y=as.bigz(rep(0,10000)); len=0; n=as.bigz(-1)
while(len<10000) if(isprime(trimR((n=n+1)^3))) y[(len=len+1)]=n^3
A226098
Fifth powers that become prime when their most significant (leftmost) decimal digit is removed.
Original entry on oeis.org
32, 243, 59049, 161051, 371293, 6436343, 14348907, 115856201, 282475249, 844596301, 73439775749, 173726604657, 312079600999, 779811265199, 2553954421743, 2817036000549, 3515706497843, 5798839393557, 10112638401999, 12914277518099, 14530697473149
Offset: 1
a(1) = 2^5 = 32 because when its most significant (or leftmost) digit (3) is removing the remaining 2 is prime.
A226100
Main diagonal A(n,n) of matrix A(k,n) = n-th k-th power that becomes prime when its most significant (i.e., leftmost) decimal digit is removed.
Original entry on oeis.org
12, 289, 729, 20151121, 371293, 2839760855281, 24160660561265139, 241100240228887100161, 3421941488772218992567, 845219547726738091164049, 7506514445791062595879589895041, 293936151563356954592299567713259041, 6657844787831219696900816415217242830357
Offset: 1
a(1) = A(1,1) = 12 = first number whose first power (itself) becomes prime when its most significant (or leftmost) digit is removed.
a(2) = A(2,2) = 289 = second square which becomes prime when its most significant (or leftmost) digit is removed.
a(3) =
Showing 1-4 of 4 results.
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