A115430
Numbers k such that the concatenation of k with k+9 gives a square.
Original entry on oeis.org
216, 287, 515, 675, 1175, 4320, 82640, 960795, 1322312, 4049591, 16955015, 34602080, 171010235, 181964891, 183673467, 187160072, 321920055, 326530616, 328818032, 343942560, 470954312, 526023432, 528925616, 534830855
Offset: 1
Cf.
A030465,
A102567,
A115426,
A115437,
A115428,
A115429,
A115431,
A115432,
A115433,
A115434,
A115435,
A115436,
A115441.
A116324
Numbers k such that k * (k+5) gives the concatenation of two numbers m and m+5.
Original entry on oeis.org
31, 65, 42754, 57242, 75424, 425073, 574923, 979529, 4301394, 5698602, 7028667, 4925000748, 5074999248, 7748266575, 8511881485, 8814851185, 7059602159673, 7106167933829, 7439286611622, 7485852385778, 46791112884926
Offset: 1
-
f:= proc(d) local S,R,r,s,m,n;
r:= 10^d+1;
S:= map(t -> rhs(op(t)), [msolve(n*(n+5)=5,r)]);
S:= select(proc(s) local t; t:= (s*(s+5)-5)/r; t+5 >= (r-1)/10 and t+5 < r-1 end proc, S);
op(sort(S));
end proc:
map(f, [$1..20]); # Robert Israel, Jun 21 2024
A116317
Numbers k such that k*(k+4) gives the concatenation of two numbers m and m+4.
Original entry on oeis.org
7745, 8019, 33294316, 66705681, 98000199, 340465755423, 476452552743, 523547447254, 659534244574, 866013200679, 998000001999, 3695104677080132, 3755782995538766, 4198081170077529, 4803478892324964, 5196521107675033
Offset: 1
98000199 * 98000203 = 96040393//96040397, where // denotes concatenation.
A116337
Numbers k such that k*(k+4) gives the concatenation of two numbers m and m+7.
Original entry on oeis.org
8217108, 8030443878983905982, 43467818511541680701794365325328847002052, 56532181488458319298205634674671152997945
Offset: 1
8217108 * 8217112 = 6752089//6752096, where // denotes concatenation.
A116322
Numbers k such that k*(k+1) gives the concatenation of two numbers m and m+5.
Original entry on oeis.org
41, 59, 32262233, 67737767, 79321057, 3341093417798787499094, 3861488851737861033962, 4747922651210186579788, 5252077348789813420212, 6138511148262138966038, 6658906582201212500906, 7232275368591793618232
Offset: 1
79321057 * 79321058 = 62918301//62918306, where // denotes concatenation.
Showing 1-5 of 5 results.
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