A069661
Smallest n-digit prime with maximum digit sum.
Original entry on oeis.org
7, 89, 997, 8999, 98999, 989999, 9899999, 89999999, 998999999, 9899989999, 98999999999, 999998999999, 8998999999999, 99899999999999, 999999899999999, 9998999999999999, 99999999999899999, 999998999999999999, 9998999999999999999, 89999999999999999999
Offset: 1
a(n) =
A069662(n) for these n <= 20: 1, 2, 3, 4, 6, 7, 9, 17 and 19. a(5) = Reverse(
A069662(5)).
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Table[max=0; Do[p=Prime[i]; If[Total[IntegerDigits[p]] > Total[IntegerDigits[max]], max=p], {i,PrimePi[10^n]+1, PrimePi[10^(n+1)]}]; max, {n,0,7}] (* Jayanta Basu, May 19 2013 *)
Corrected and extended by
Rick L. Shepherd, Jul 15 2002. a(5) through a(20) have been certified prime with Primo.
A069663
Smallest n-digit prime with minimum digit sum.
Original entry on oeis.org
2, 11, 101, 1021, 10111, 100003, 1000003, 10010101, 101001001, 1000000021, 10000001101, 100000000003, 1000000020001, 10000000001011, 100000000100101, 1000000000100011, 10000000000001101, 100000000000000003
Offset: 1
a(5) = 10111 is the least prime with digit sum 4 and no other/smaller 5 digit prime has a digit sum 4 or less.
A069664
Largest n-digit prime with minimum digit sum.
Original entry on oeis.org
2, 11, 101, 3001, 21001, 102001, 2100001, 30000001, 200001001, 2010000001, 30000000001, 110000000101, 2000001000001, 20000000100001, 200000010000001, 1100010000000001, 20000001000000001, 110000000000000101, 2000000000000100001, 20000000100000000001
Offset: 1
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Table[ Max[ Flatten[Table[ If[PrimeQ[10^n + 1], 10^n + 1, If[PrimeQ[10^n + 10^i + 10^j + 1], 10^n + 10^i + 10^j + 1, 0]], {i, 0, n}, {j, 0, i}]]], {n, 0, 50}] (* Program works so long as there exists an n-digit prime with digit sum 4 or less. *)
A069665
Smallest n-digit square with maximum digit sum.
Original entry on oeis.org
9, 49, 289, 6889, 97969, 698896, 9696996, 79869969, 876988996, 8998988769, 88998998929, 975979998889, 9998768898889, 97888999968769, 898999897988929, 9895699989899689, 38999699989995889, 989879999979599689
Offset: 1
More terms from Larry Reeves (larryr(AT)acm.org), Oct 14 2003
A069666
Largest n-digit square with maximum digit sum.
Original entry on oeis.org
9, 49, 784, 6889, 97969, 877969, 9696996, 88679889, 876988996, 8998988769, 88998998929, 975979998889, 9998768898889, 97888999968769, 898999897988929, 9896999999766889, 99497897999899876, 989879999979599689
Offset: 1
Corrected and extended by Larry Reeves (larryr(AT)acm.org), Oct 14 2003
A069667
Smallest nontrivial (no trailing zeros) n-digit square with minimum digit sum.
Original entry on oeis.org
1, 16, 121, 1024, 10201, 101124, 1002001, 24000201, 100020001, 2500100001, 10000200001, 141001001001, 1000002000001, 25000010000001, 100000020000001, 2500000100000001, 10000000200000001, 250000001000000001
Offset: 1
More terms from Larry Reeves (larryr(AT)acm.org), Oct 15 2003
A069668
Largest nontrivial (no trailing zeros) n-digit square with minimum digit sum.
Original entry on oeis.org
1, 25, 121, 2401, 10201, 301401, 1002001, 25010001, 100020001, 2500100001, 10000200001, 250001000001, 1000002000001, 25000010000001, 100000020000001, 2500000100000001, 10000000200000001, 250000001000000001
Offset: 1
Corrected and extended by Larry Reeves (larryr(AT)acm.org), Oct 15 2003
A069669
Smallest n-digit triangular number with maximum digit sum.
Original entry on oeis.org
6, 78, 496, 8778, 58996, 887778, 5897895, 88877778, 686999778, 9876799878, 89996788896, 777887999778, 7798988788878, 77779987999896, 589598998999878, 7898898998885986, 78999997699698778, 999699998689998991
Offset: 1
More terms from Larry Reeves (larryr(AT)acm.org), Oct 15 2003
A069670
Largest n-digit triangular number with maximum digit sum.
Original entry on oeis.org
6, 78, 946, 8778, 58996, 998991, 9979278, 98989485, 886899786, 9998888991, 89996788896, 999998497578, 9869988988965, 99989985868878, 988895779999896, 9999678588989986, 99889886986899778, 999699998689998991
Offset: 1
More terms from Larry Reeves (larryr(AT)acm.org), Oct 15 2003
A069671
Smallest n-digit triangular number with minimum digit sum.
Original entry on oeis.org
1, 10, 120, 2211, 10011, 112101, 2001000, 10006101, 200010000, 1210000221, 20000100000, 210010000005, 2000001000000, 32000004000000, 200000010000000, 3200000040000000, 20000000100000000, 320000000400000000, 2000000001000000000, 32000000004000000000
Offset: 1
Showing 1-10 of 11 results.
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