A056749 Smallest palindrome greater than n in bases 2 and n.

3, 6643, 5, 31, 7, 85, 9, 127, 33, 255, 65, 313, 15, 693, 17, 341, 325, 381, 21, 1241, 771, 645, 325, 951, 27, 5461, 1317, 1161, 31, 1241, 33, 1453, 455, 5709, 3999, 2925, 195, 4097, 1025, 7671, 129, 2409, 45, 4097, 4095, 3855, 1421, 5049, 51, 8673, 3069

Offset: 2

Author

Robert G. Wilson v, Aug 15 2000

Keywords

• nonn
• base

Links

• Michel Marcus, Table of n, a(n) for n = 2..1000

Crossrefs

Cf. A048268 (bases n and n+1).

Programs

Mathematica

Do[ k = n +1; While[ RealDigits[ k, n ][ [ 1 ] ] != Reverse[ RealDigits[ k, n ][ [ 1 ] ] ] || RealDigits[ k, 2 ][ [ 1 ] ] != Reverse[ RealDigits[ k, 2 ][ [ 1 ] ] ], k++ ]; Print[ k ], {n, 2, 60} ]

PARI

isok2(j, n) = my(d=digits(j,n), b=binary(j)); (Vecrev(d)==d) && (Vecrev(b)==b);
a(n) = {my(j = n); while(! isok2(j, n), j++); j;} \\ Michel Marcus, Nov 16 2017