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 A249893 a(n+1) is next smallest square not divisible by 10 beginning with a(n), initial term is 2. 4
 2, 25, 256, 256036, 2560361612769, 256036161276932002260000001, 256036161276932002260000001607597862784080913990785121 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(12) has 1717 digits. - Michael S. Branicky, Feb 25 2021 LINKS Michael S. Branicky, Table of n, a(n) for n = 1..11 (terms 1..10 from Hiroaki Yamanouchi) PROG (PARI) a(n)=k=n; s=1; while(s<5*10^7, if(s%10, if(s^2\(10^(#Str(s^2)-#Str(k)))==k, print1(s^2, ", "); k=s^2)); s++) a(2) (Python) def f(x): ..print(x, end=', ') ..n = x ..s = 1 ..while s < 10**7: ....if s % 10: ......S = str(s**2) ......if S.startswith(str(n)): ........print(s**2, end=', ') ........n = s**2 ....s += 1 f(2) (Python) from math import isqrt def anext(an):   lo, hi = an*10, an*10 + 9   while True:     found = False     if isqrt(hi)**2 > lo: return (isqrt(lo)+1)**2     lo, hi = lo*10, hi*10 + 9 n, an = 1, 2 for n in range(2, 17):   an = anext(an)   print(n, an) # Michael S. Branicky, Feb 25 2021 CROSSREFS Cf. A048559, A048561. Sequence in context: A042919 A229975 A174970 * A085830 A270346 A212022 Adjacent sequences:  A249890 A249891 A249892 * A249894 A249895 A249896 KEYWORD nonn,base AUTHOR Derek Orr, Nov 08 2014 STATUS approved

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Last modified May 20 08:03 EDT 2022. Contains 353852 sequences. (Running on oeis4.)