This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A230953 #21 Jun 12 2022 12:23:32 %S A230953 3,8,20,53,154,505,1944,8651,44046,252271,1605874,11245261,85907084, %T A230953 710970323,6336648426,60510526207,616355168958,6670526004559, %U A230953 76438597647616,924584128977111,11772170758462928,157382330019694067,2204239468545788024,32275035859881159165 %N A230953 Boustrophedon transform of odd primes, cf. A065091. %H A230953 Reinhard Zumkeller, <a href="/A230953/b230953.txt">Table of n, a(n) for n = 0..400</a> %H A230953 Peter Luschny, <a href="http://oeis.org/wiki/User:Peter_Luschny/SeidelTransform">An old operation on sequences: the Seidel transform</a> %H A230953 J. Millar, N. J. A. Sloane and N. E. Young, A new operation on sequences: the Boustrophedon transform, J. Combin. Theory, 17A 44-54 1996 (<a href="http://neilsloane.com/doc/bous.txt">Abstract</a>, <a href="http://neilsloane.com/doc/bous.pdf">pdf</a>, <a href="http://neilsloane.com/doc/bous.ps">ps</a>). %H A230953 Wikipedia, <a href="http://en.wikipedia.org/wiki/Boustrophedon_transform">Boustrophedon transform</a> %H A230953 <a href="/index/Bo#boustrophedon">Index entries for sequences related to boustrophedon transform</a> %F A230953 a(n) = Sum_{k=0..n} A109449(n,k)*A000040(k+2). %F A230953 E.g.f.: (sec(x) + tan(x)) * Sum_{k>=0} prime(k+2)*x^k/k!. - _Ilya Gutkovskiy_, Jun 26 2018 %t A230953 t[n_, 0] := Prime[n+2]; t[n_, k_] := t[n, k] = t[n, k-1] + t[n-1, n-k]; a[n_] := t[n, n]; Array[a, 30, 0] (* _Jean-François Alcover_, Feb 12 2016 *) %o A230953 (Haskell) %o A230953 a230953 n = sum $ zipWith (*) (a109449_row n) $ tail a000040_list %o A230953 (Python) %o A230953 from itertools import accumulate, count, islice %o A230953 from sympy import prime %o A230953 def A230953_gen(): # generator of terms %o A230953 blist = tuple() %o A230953 for i in count(2): %o A230953 yield (blist := tuple(accumulate(reversed(blist),initial=prime(i))))[-1] %o A230953 A230953_list = list(islice(A230953_gen(),40)) # _Chai Wah Wu_, Jun 12 2022 %Y A230953 Cf. A000747, A230956, A230954, A230955. %K A230953 nonn %O A230953 0,1 %A A230953 _Reinhard Zumkeller_, Nov 03 2013