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 A259385 Palindromic numbers in bases 2 and 9 written in base 10. 16
 0, 1, 3, 5, 7, 127, 255, 273, 455, 6643, 17057, 19433, 19929, 42405, 1245161, 1405397, 1786971, 2122113, 3519339, 4210945, 67472641, 90352181, 133638015, 134978817, 271114881, 6080408749, 11022828069, 24523959661, 25636651261, 25726334461, 28829406059, 1030890430479, 1032991588623, 1085079274815, 1616662113341 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Giovanni Resta, Table of n, a(n) for n = 1..44 FORMULA Intersection of A006995 and A029955. EXAMPLE 273 is in the sequence because 273_10 = 333_9 = 100010001_2. MATHEMATICA (* first load nthPalindromeBase from A002113 *) palQ[n_Integer, base_Integer] := Block[{}, Reverse[ idn = IntegerDigits[n, base]] == idn]; k = 0; lst = {}; While[k < 21000000, pp = nthPalindromeBase[k, 9]; If[palQ[pp, 2], AppendTo[lst, pp]; Print[pp]]; k++]; lst PROG (Python) def nextpal(n, base): # m is the first palindrome successor of n in base base     m, pl = n+1, 0     while m > 0:         m, pl = m//base, pl+1     if n+1 == base**pl:         pl = pl+1     n = n//(base**(pl//2))+1     m, n = n, n//(base**(pl%2))     while n > 0:         m, n = m*base+n%base, n//base     return m n, a2, a9 = 0, 0, 0 while n <= 30:     if a2 < a9:         a2 = nextpal(a2, 2)     elif a9 < a2:         a9 = nextpal(a9, 9)     else: # a2 == a9         print(a2, end=", ")         a2, a9, n = nextpal(a2, 2), nextpal(a9, 9), n+1 # A.H.M. Smeets, Jun 03 2019 CROSSREFS Cf. A048268, A060792, A097856, A097928, A182232, A259374, A097929, A182233, A259375, A259376, A097930, A182234, A259377, A259378, A249156, A097931, A259380, A259381, A259382, A259383, A259384, A099145, A259385, A259386, A259387, A259388, A259389, A259390, A099146, A007632, A007633, A029961, A029962, A029963, A029964, A029804, A029965, A029966, A029967, A029968, A029969, A029970, A029731, A097855, A250408, A250409, A250410, A250411, A099165, A250412. Sequence in context: A046201 A292848 A128344 * A114366 A088092 A174271 Adjacent sequences:  A259382 A259383 A259384 * A259386 A259387 A259388 KEYWORD nonn,base AUTHOR Eric A. Schmidt and Robert G. Wilson v, Jul 16 2015 STATUS approved

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Last modified May 27 18:56 EDT 2020. Contains 334664 sequences. (Running on oeis4.)